{"license":"https://creativecommons.org/licenses/by/4.0/","dataset":"hhi-decomposition","count":105,"filters":{"comparisonMode":"adjacent_releases","framework":"guidelines_2023","from":null,"residualFirmAssumption":4,"to":null,"repaired":[]},"summary":{"availableMarketCount":4,"availableReleaseCount":16,"availableAdjacentComparisonCount":12,"availableYearPairCount":24,"selectedComparisonCount":12,"selectedMarketCount":4,"selectedParticipantRowCount":105,"selectedSourceCount":4},"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions.","rows":[{"comparisonId":"us-search-engine-usage-2023-2024-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":7899.6544,"fromScenarioHhi":7950,"fromSharePercent":88.88,"fromSourceId":"statcounter-search-us-2026","fromYear":2023,"hhiContributionChange":-403.558,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-375,"participantLabel":"Google Search","participantSlug":"google-search","participantStatus":"continuing","possibleHhiChangeCeiling":-375,"possibleHhiChangeFloor":-375,"residualFirmAssumption":4,"scenarioHhiChange":-375,"shareChangePoints":-2.3,"toClassification":"highly_concentrated","toHhiContribution":7496.0964,"toScenarioHhi":7575,"toSharePercent":86.58,"toSourceId":"statcounter-search-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":41.3449,"fromScenarioHhi":7950,"fromSharePercent":6.43,"fromSourceId":"statcounter-search-us-2026","fromYear":2023,"hhiContributionChange":26.5527,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-375,"participantLabel":"Bing","participantSlug":"bing","participantStatus":"continuing","possibleHhiChangeCeiling":-375,"possibleHhiChangeFloor":-375,"residualFirmAssumption":4,"scenarioHhiChange":-375,"shareChangePoints":1.81,"toClassification":"highly_concentrated","toHhiContribution":67.8976,"toScenarioHhi":7575,"toSharePercent":8.24,"toSourceId":"statcounter-search-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":5.4289,"fromScenarioHhi":7950,"fromSharePercent":2.33,"fromSourceId":"statcounter-search-us-2026","fromYear":2023,"hhiContributionChange":1.2792,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-375,"participantLabel":"Yahoo Search","participantSlug":"yahoo-search","participantStatus":"continuing","possibleHhiChangeCeiling":-375,"possibleHhiChangeFloor":-375,"residualFirmAssumption":4,"scenarioHhiChange":-375,"shareChangePoints":0.26,"toClassification":"highly_concentrated","toHhiContribution":6.7081,"toScenarioHhi":7575,"toSharePercent":2.59,"toSourceId":"statcounter-search-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":3.9204,"fromScenarioHhi":7950,"fromSharePercent":1.98,"fromSourceId":"statcounter-search-us-2026","fromYear":2023,"hhiContributionChange":0.406,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-375,"participantLabel":"DuckDuckGo","participantSlug":"duckduckgo","participantStatus":"continuing","possibleHhiChangeCeiling":-375,"possibleHhiChangeFloor":-375,"residualFirmAssumption":4,"scenarioHhiChange":-375,"shareChangePoints":0.1,"toClassification":"highly_concentrated","toHhiContribution":4.3264,"toScenarioHhi":7575,"toSharePercent":2.08,"toSourceId":"statcounter-search-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0225,"fromScenarioHhi":7950,"fromSharePercent":0.15,"fromSourceId":"statcounter-search-us-2026","fromYear":2023,"hhiContributionChange":0.0259,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-375,"participantLabel":"Yandex","participantSlug":"yandex","participantStatus":"continuing","possibleHhiChangeCeiling":-375,"possibleHhiChangeFloor":-375,"residualFirmAssumption":4,"scenarioHhiChange":-375,"shareChangePoints":0.07,"toClassification":"highly_concentrated","toHhiContribution":0.0484,"toScenarioHhi":7575,"toSharePercent":0.22,"toSourceId":"statcounter-search-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2023-2024-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0064,"fromScenarioHhi":7950,"fromSharePercent":0.16,"fromSourceId":"statcounter-search-us-2026","fromYear":2023,"hhiContributionChange":0.0046,"isResidual":true,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-375,"participantLabel":"Other search engines","participantSlug":"other-search-engines","participantStatus":"residual","possibleHhiChangeCeiling":-375,"possibleHhiChangeFloor":-375,"residualFirmAssumption":4,"scenarioHhiChange":-375,"shareChangePoints":0.05,"toClassification":"highly_concentrated","toHhiContribution":0.011,"toScenarioHhi":7575,"toSharePercent":0.21,"toSourceId":"statcounter-search-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2023-2024-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0049,"fromScenarioHhi":7950,"fromSharePercent":0.07,"fromSourceId":"statcounter-search-us-2026","fromYear":2023,"hhiContributionChange":0.0015,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-375,"participantLabel":"Ecosia","participantSlug":"ecosia","participantStatus":"continuing","possibleHhiChangeCeiling":-375,"possibleHhiChangeFloor":-375,"residualFirmAssumption":4,"scenarioHhiChange":-375,"shareChangePoints":0.01,"toClassification":"highly_concentrated","toHhiContribution":0.0064,"toScenarioHhi":7575,"toSharePercent":0.08,"toSourceId":"statcounter-search-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2024-2025-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":7496.0964,"fromScenarioHhi":7575,"fromSharePercent":86.58,"fromSourceId":"statcounter-search-us-2026","fromYear":2024,"hhiContributionChange":22.5277,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":14,"participantLabel":"Google Search","participantSlug":"google-search","participantStatus":"continuing","possibleHhiChangeCeiling":14,"possibleHhiChangeFloor":14,"residualFirmAssumption":4,"scenarioHhiChange":14,"shareChangePoints":0.13,"toClassification":"highly_concentrated","toHhiContribution":7518.6241,"toScenarioHhi":7589,"toSharePercent":86.71,"toSourceId":"statcounter-search-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":67.8976,"fromScenarioHhi":7575,"fromSharePercent":8.24,"fromSourceId":"statcounter-search-us-2026","fromYear":2024,"hhiContributionChange":-11.6476,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":14,"participantLabel":"Bing","participantSlug":"bing","participantStatus":"continuing","possibleHhiChangeCeiling":14,"possibleHhiChangeFloor":14,"residualFirmAssumption":4,"scenarioHhiChange":14,"shareChangePoints":-0.74,"toClassification":"highly_concentrated","toHhiContribution":56.25,"toScenarioHhi":7589,"toSharePercent":7.5,"toSourceId":"statcounter-search-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2024-2025-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":6.7081,"fromScenarioHhi":7575,"fromSharePercent":2.59,"fromSourceId":"statcounter-search-us-2026","fromYear":2024,"hhiContributionChange":1.4715,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":14,"participantLabel":"Yahoo Search","participantSlug":"yahoo-search","participantStatus":"continuing","possibleHhiChangeCeiling":14,"possibleHhiChangeFloor":14,"residualFirmAssumption":4,"scenarioHhiChange":14,"shareChangePoints":0.27,"toClassification":"highly_concentrated","toHhiContribution":8.1796,"toScenarioHhi":7589,"toSharePercent":2.86,"toSourceId":"statcounter-search-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2024-2025-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":4.3264,"fromScenarioHhi":7575,"fromSharePercent":2.08,"fromSourceId":"statcounter-search-us-2026","fromYear":2024,"hhiContributionChange":1.1492,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":14,"participantLabel":"DuckDuckGo","participantSlug":"duckduckgo","participantStatus":"continuing","possibleHhiChangeCeiling":14,"possibleHhiChangeFloor":14,"residualFirmAssumption":4,"scenarioHhiChange":14,"shareChangePoints":0.26,"toClassification":"highly_concentrated","toHhiContribution":5.4756,"toScenarioHhi":7589,"toSharePercent":2.34,"toSourceId":"statcounter-search-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2024-2025-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0484,"fromScenarioHhi":7575,"fromSharePercent":0.22,"fromSourceId":"statcounter-search-us-2026","fromYear":2024,"hhiContributionChange":0.054,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":14,"participantLabel":"Yandex","participantSlug":"yandex","participantStatus":"continuing","possibleHhiChangeCeiling":14,"possibleHhiChangeFloor":14,"residualFirmAssumption":4,"scenarioHhiChange":14,"shareChangePoints":0.1,"toClassification":"highly_concentrated","toHhiContribution":0.1024,"toScenarioHhi":7589,"toSharePercent":0.32,"toSourceId":"statcounter-search-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2024-2025-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.011,"fromScenarioHhi":7575,"fromSharePercent":0.21,"fromSourceId":"statcounter-search-us-2026","fromYear":2024,"hhiContributionChange":-0.0029,"isResidual":true,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":14,"participantLabel":"Other search engines","participantSlug":"other-search-engines","participantStatus":"residual","possibleHhiChangeCeiling":14,"possibleHhiChangeFloor":14,"residualFirmAssumption":4,"scenarioHhiChange":14,"shareChangePoints":-0.03,"toClassification":"highly_concentrated","toHhiContribution":0.0081,"toScenarioHhi":7589,"toSharePercent":0.18,"toSourceId":"statcounter-search-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2024-2025-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0064,"fromScenarioHhi":7575,"fromSharePercent":0.08,"fromSourceId":"statcounter-search-us-2026","fromYear":2024,"hhiContributionChange":0.0017,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":14,"participantLabel":"Ecosia","participantSlug":"ecosia","participantStatus":"continuing","possibleHhiChangeCeiling":14,"possibleHhiChangeFloor":14,"residualFirmAssumption":4,"scenarioHhiChange":14,"shareChangePoints":0.01,"toClassification":"highly_concentrated","toHhiContribution":0.0081,"toScenarioHhi":7589,"toSharePercent":0.09,"toSourceId":"statcounter-search-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":7518.6241,"fromScenarioHhi":7589,"fromSharePercent":86.71,"fromSourceId":"statcounter-search-us-2026","fromYear":2025,"hhiContributionChange":-266.3985,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-230,"participantLabel":"Google Search","participantSlug":"google-search","participantStatus":"continuing","possibleHhiChangeCeiling":-230,"possibleHhiChangeFloor":-230,"residualFirmAssumption":4,"scenarioHhiChange":-230,"shareChangePoints":-1.55,"toClassification":"highly_concentrated","toHhiContribution":7252.2256,"toScenarioHhi":7359,"toSharePercent":85.16,"toSourceId":"statcounter-search-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2025-2026-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":56.25,"fromScenarioHhi":7589,"fromSharePercent":7.5,"fromSourceId":"statcounter-search-us-2026","fromYear":2025,"hhiContributionChange":40.1824,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-230,"participantLabel":"Bing","participantSlug":"bing","participantStatus":"continuing","possibleHhiChangeCeiling":-230,"possibleHhiChangeFloor":-230,"residualFirmAssumption":4,"scenarioHhiChange":-230,"shareChangePoints":2.32,"toClassification":"highly_concentrated","toHhiContribution":96.4324,"toScenarioHhi":7359,"toSharePercent":9.82,"toSourceId":"statcounter-search-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":5.4756,"fromScenarioHhi":7589,"fromSharePercent":2.34,"fromSourceId":"statcounter-search-us-2026","fromYear":2025,"hhiContributionChange":-2.448,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-230,"participantLabel":"DuckDuckGo","participantSlug":"duckduckgo","participantStatus":"continuing","possibleHhiChangeCeiling":-230,"possibleHhiChangeFloor":-230,"residualFirmAssumption":4,"scenarioHhiChange":-230,"shareChangePoints":-0.6,"toClassification":"highly_concentrated","toHhiContribution":3.0276,"toScenarioHhi":7359,"toSharePercent":1.74,"toSourceId":"statcounter-search-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":8.1796,"fromScenarioHhi":7589,"fromSharePercent":2.86,"fromSourceId":"statcounter-search-us-2026","fromYear":2025,"hhiContributionChange":-1.0507,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-230,"participantLabel":"Yahoo Search","participantSlug":"yahoo-search","participantStatus":"continuing","possibleHhiChangeCeiling":-230,"possibleHhiChangeFloor":-230,"residualFirmAssumption":4,"scenarioHhiChange":-230,"shareChangePoints":-0.19,"toClassification":"highly_concentrated","toHhiContribution":7.1289,"toScenarioHhi":7359,"toSharePercent":2.67,"toSourceId":"statcounter-search-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2025-2026-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.1024,"fromScenarioHhi":7589,"fromSharePercent":0.32,"fromSourceId":"statcounter-search-us-2026","fromYear":2025,"hhiContributionChange":0.042,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-230,"participantLabel":"Yandex","participantSlug":"yandex","participantStatus":"continuing","possibleHhiChangeCeiling":-230,"possibleHhiChangeFloor":-230,"residualFirmAssumption":4,"scenarioHhiChange":-230,"shareChangePoints":0.06,"toClassification":"highly_concentrated","toHhiContribution":0.1444,"toScenarioHhi":7359,"toSharePercent":0.38,"toSourceId":"statcounter-search-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2025-2026-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0081,"fromScenarioHhi":7589,"fromSharePercent":0.18,"fromSourceId":"statcounter-search-us-2026","fromYear":2025,"hhiContributionChange":-0.0045,"isResidual":true,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-230,"participantLabel":"Other search engines","participantSlug":"other-search-engines","participantStatus":"residual","possibleHhiChangeCeiling":-230,"possibleHhiChangeFloor":-230,"residualFirmAssumption":4,"scenarioHhiChange":-230,"shareChangePoints":-0.06,"toClassification":"highly_concentrated","toHhiContribution":0.0036,"toScenarioHhi":7359,"toSharePercent":0.12,"toSourceId":"statcounter-search-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-search-engine-usage-2025-2026-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0081,"fromScenarioHhi":7589,"fromSharePercent":0.09,"fromSourceId":"statcounter-search-us-2026","fromYear":2025,"hhiContributionChange":0.004,"isResidual":false,"marketName":"U.S. search engine usage","marketSlug":"us-search-engine-usage","observedHhiChange":-230,"participantLabel":"Ecosia","participantSlug":"ecosia","participantStatus":"continuing","possibleHhiChangeCeiling":-230,"possibleHhiChangeFloor":-230,"residualFirmAssumption":4,"scenarioHhiChange":-230,"shareChangePoints":0.02,"toClassification":"highly_concentrated","toHhiContribution":0.0121,"toScenarioHhi":7359,"toSharePercent":0.11,"toSourceId":"statcounter-search-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":2363.9044,"fromScenarioHhi":3654,"fromSharePercent":48.62,"fromSourceId":"statcounter-browser-us-2026","fromYear":2023,"hhiContributionChange":440.8572,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":182,"participantLabel":"Chrome","participantSlug":"chrome","participantStatus":"continuing","possibleHhiChangeCeiling":195,"possibleHhiChangeFloor":174,"residualFirmAssumption":4,"scenarioHhiChange":186,"shareChangePoints":4.34,"toClassification":"highly_concentrated","toHhiContribution":2804.7616,"toScenarioHhi":3840,"toSharePercent":52.96,"toSourceId":"statcounter-browser-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2023-2024-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":1202.7024,"fromScenarioHhi":3654,"fromSharePercent":34.68,"fromSourceId":"statcounter-browser-us-2026","fromYear":2023,"hhiContributionChange":-244.7999,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":182,"participantLabel":"Safari","participantSlug":"safari","participantStatus":"continuing","possibleHhiChangeCeiling":195,"possibleHhiChangeFloor":174,"residualFirmAssumption":4,"scenarioHhiChange":186,"shareChangePoints":-3.73,"toClassification":"highly_concentrated","toHhiContribution":957.9025,"toScenarioHhi":3840,"toSharePercent":30.95,"toSourceId":"statcounter-browser-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2023-2024-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":71.4025,"fromScenarioHhi":3654,"fromSharePercent":8.45,"fromSourceId":"statcounter-browser-us-2026","fromYear":2023,"hhiContributionChange":-16.1976,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":182,"participantLabel":"Edge","participantSlug":"edge","participantStatus":"continuing","possibleHhiChangeCeiling":195,"possibleHhiChangeFloor":174,"residualFirmAssumption":4,"scenarioHhiChange":186,"shareChangePoints":-1.02,"toClassification":"highly_concentrated","toHhiContribution":55.2049,"toScenarioHhi":3840,"toSharePercent":7.43,"toSourceId":"statcounter-browser-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":11.4921,"fromScenarioHhi":3654,"fromSharePercent":3.39,"fromSourceId":"statcounter-browser-us-2026","fromYear":2023,"hhiContributionChange":6.232,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":182,"participantLabel":"Firefox","participantSlug":"firefox","participantStatus":"continuing","possibleHhiChangeCeiling":195,"possibleHhiChangeFloor":174,"residualFirmAssumption":4,"scenarioHhiChange":186,"shareChangePoints":0.82,"toClassification":"highly_concentrated","toHhiContribution":17.7241,"toScenarioHhi":3840,"toSharePercent":4.21,"toSourceId":"statcounter-browser-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2023-2024-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":3.1329,"fromScenarioHhi":3654,"fromSharePercent":3.54,"fromSourceId":"statcounter-browser-us-2026","fromYear":2023,"hhiContributionChange":-1.1307,"isResidual":true,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":182,"participantLabel":"Other browsers","participantSlug":"other-browsers","participantStatus":"residual","possibleHhiChangeCeiling":195,"possibleHhiChangeFloor":174,"residualFirmAssumption":4,"scenarioHhiChange":186,"shareChangePoints":-0.71,"toClassification":"highly_concentrated","toHhiContribution":2.0022,"toScenarioHhi":3840,"toSharePercent":2.83,"toSourceId":"statcounter-browser-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":1.7424,"fromScenarioHhi":3654,"fromSharePercent":1.32,"fromSourceId":"statcounter-browser-us-2026","fromYear":2023,"hhiContributionChange":0.882,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":182,"participantLabel":"Samsung Internet","participantSlug":"samsung-internet","participantStatus":"continuing","possibleHhiChangeCeiling":195,"possibleHhiChangeFloor":174,"residualFirmAssumption":4,"scenarioHhiChange":186,"shareChangePoints":0.3,"toClassification":"highly_concentrated","toHhiContribution":2.6244,"toScenarioHhi":3840,"toSharePercent":1.62,"toSourceId":"statcounter-browser-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2023-2024-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0,"fromScenarioHhi":3654,"fromSharePercent":0,"fromSourceId":"statcounter-browser-us-2026","fromYear":2023,"hhiContributionChange":0,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":182,"participantLabel":"Brave","participantSlug":"brave","participantStatus":"continuing","possibleHhiChangeCeiling":195,"possibleHhiChangeFloor":174,"residualFirmAssumption":4,"scenarioHhiChange":186,"shareChangePoints":0,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":3840,"toSharePercent":0,"toSourceId":"statcounter-browser-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":2804.7616,"fromScenarioHhi":3840,"fromSharePercent":52.96,"fromSourceId":"statcounter-browser-us-2026","fromYear":2024,"hhiContributionChange":-67.3792,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-126,"participantLabel":"Chrome","participantSlug":"chrome","participantStatus":"continuing","possibleHhiChangeCeiling":-118,"possibleHhiChangeFloor":-132,"residualFirmAssumption":4,"scenarioHhiChange":-125,"shareChangePoints":-0.64,"toClassification":"highly_concentrated","toHhiContribution":2737.3824,"toScenarioHhi":3716,"toSharePercent":52.32,"toSourceId":"statcounter-browser-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":957.9025,"fromScenarioHhi":3840,"fromSharePercent":30.95,"fromSourceId":"statcounter-browser-us-2026","fromYear":2024,"hhiContributionChange":-57.3024,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-126,"participantLabel":"Safari","participantSlug":"safari","participantStatus":"continuing","possibleHhiChangeCeiling":-118,"possibleHhiChangeFloor":-132,"residualFirmAssumption":4,"scenarioHhiChange":-125,"shareChangePoints":-0.94,"toClassification":"highly_concentrated","toHhiContribution":900.6001,"toScenarioHhi":3716,"toSharePercent":30.01,"toSourceId":"statcounter-browser-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2024-2025-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0,"fromScenarioHhi":3840,"fromSharePercent":0,"fromSourceId":"statcounter-browser-us-2026","fromYear":2024,"hhiContributionChange":6.0516,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-126,"participantLabel":"Brave","participantSlug":"brave","participantStatus":"entered","possibleHhiChangeCeiling":-118,"possibleHhiChangeFloor":-132,"residualFirmAssumption":4,"scenarioHhiChange":-125,"shareChangePoints":2.46,"toClassification":"highly_concentrated","toHhiContribution":6.0516,"toScenarioHhi":3716,"toSharePercent":2.46,"toSourceId":"statcounter-browser-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":55.2049,"fromScenarioHhi":3840,"fromSharePercent":7.43,"fromSourceId":"statcounter-browser-us-2026","fromYear":2024,"hhiContributionChange":-4.7949,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-126,"participantLabel":"Edge","participantSlug":"edge","participantStatus":"continuing","possibleHhiChangeCeiling":-118,"possibleHhiChangeFloor":-132,"residualFirmAssumption":4,"scenarioHhiChange":-125,"shareChangePoints":-0.33,"toClassification":"highly_concentrated","toHhiContribution":50.41,"toScenarioHhi":3716,"toSharePercent":7.1,"toSourceId":"statcounter-browser-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":2.0022,"fromScenarioHhi":3840,"fromSharePercent":2.83,"fromSourceId":"statcounter-browser-us-2026","fromYear":2024,"hhiContributionChange":-0.5622,"isResidual":true,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-126,"participantLabel":"Other browsers","participantSlug":"other-browsers","participantStatus":"residual","possibleHhiChangeCeiling":-118,"possibleHhiChangeFloor":-132,"residualFirmAssumption":4,"scenarioHhiChange":-125,"shareChangePoints":-0.43,"toClassification":"highly_concentrated","toHhiContribution":1.44,"toScenarioHhi":3716,"toSharePercent":2.4,"toSourceId":"statcounter-browser-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":2.6244,"fromScenarioHhi":3840,"fromSharePercent":1.62,"fromSourceId":"statcounter-browser-us-2026","fromYear":2024,"hhiContributionChange":-0.2835,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-126,"participantLabel":"Samsung Internet","participantSlug":"samsung-internet","participantStatus":"continuing","possibleHhiChangeCeiling":-118,"possibleHhiChangeFloor":-132,"residualFirmAssumption":4,"scenarioHhiChange":-125,"shareChangePoints":-0.09,"toClassification":"highly_concentrated","toHhiContribution":2.3409,"toScenarioHhi":3716,"toSharePercent":1.53,"toSourceId":"statcounter-browser-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":17.7241,"fromScenarioHhi":3840,"fromSharePercent":4.21,"fromSourceId":"statcounter-browser-us-2026","fromYear":2024,"hhiContributionChange":-0.2517,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-126,"participantLabel":"Firefox","participantSlug":"firefox","participantStatus":"continuing","possibleHhiChangeCeiling":-118,"possibleHhiChangeFloor":-132,"residualFirmAssumption":4,"scenarioHhiChange":-125,"shareChangePoints":-0.03,"toClassification":"highly_concentrated","toHhiContribution":17.4724,"toScenarioHhi":3716,"toSharePercent":4.18,"toSourceId":"statcounter-browser-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":2737.3824,"fromScenarioHhi":3716,"fromSharePercent":52.32,"fromSourceId":"statcounter-browser-us-2026","fromYear":2025,"hhiContributionChange":-234.3815,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-108,"participantLabel":"Chrome","participantSlug":"chrome","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-113,"residualFirmAssumption":4,"scenarioHhiChange":-107,"shareChangePoints":-2.29,"toClassification":"highly_concentrated","toHhiContribution":2503.0009,"toScenarioHhi":3608,"toSharePercent":50.03,"toSourceId":"statcounter-browser-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2025-2026-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":900.6001,"fromScenarioHhi":3716,"fromSharePercent":30.01,"fromSourceId":"statcounter-browser-us-2026","fromYear":2025,"hhiContributionChange":114.4595,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-108,"participantLabel":"Safari","participantSlug":"safari","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-113,"residualFirmAssumption":4,"scenarioHhiChange":-107,"shareChangePoints":1.85,"toClassification":"highly_concentrated","toHhiContribution":1015.0596,"toScenarioHhi":3608,"toSharePercent":31.86,"toSourceId":"statcounter-browser-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2025-2026-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":50.41,"fromScenarioHhi":3716,"fromSharePercent":7.1,"fromSourceId":"statcounter-browser-us-2026","fromYear":2025,"hhiContributionChange":15.5244,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-108,"participantLabel":"Edge","participantSlug":"edge","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-113,"residualFirmAssumption":4,"scenarioHhiChange":-107,"shareChangePoints":1.02,"toClassification":"highly_concentrated","toHhiContribution":65.9344,"toScenarioHhi":3608,"toSharePercent":8.12,"toSourceId":"statcounter-browser-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":17.4724,"fromScenarioHhi":3716,"fromSharePercent":4.18,"fromSourceId":"statcounter-browser-us-2026","fromYear":2025,"hhiContributionChange":-3.4099,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-108,"participantLabel":"Firefox","participantSlug":"firefox","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-113,"residualFirmAssumption":4,"scenarioHhiChange":-107,"shareChangePoints":-0.43,"toClassification":"highly_concentrated","toHhiContribution":14.0625,"toScenarioHhi":3608,"toSharePercent":3.75,"toSourceId":"statcounter-browser-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2025-2026-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":6.0516,"fromScenarioHhi":3716,"fromSharePercent":2.46,"fromSourceId":"statcounter-browser-us-2026","fromYear":2025,"hhiContributionChange":1.1845,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-108,"participantLabel":"Brave","participantSlug":"brave","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-113,"residualFirmAssumption":4,"scenarioHhiChange":-107,"shareChangePoints":0.23,"toClassification":"highly_concentrated","toHhiContribution":7.2361,"toScenarioHhi":3608,"toSharePercent":2.69,"toSourceId":"statcounter-browser-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":1.44,"fromScenarioHhi":3716,"fromSharePercent":2.4,"fromSourceId":"statcounter-browser-us-2026","fromYear":2025,"hhiContributionChange":-0.327,"isResidual":true,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-108,"participantLabel":"Other browsers","participantSlug":"other-browsers","participantStatus":"residual","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-113,"residualFirmAssumption":4,"scenarioHhiChange":-107,"shareChangePoints":-0.29,"toClassification":"highly_concentrated","toHhiContribution":1.113,"toScenarioHhi":3608,"toSharePercent":2.11,"toSourceId":"statcounter-browser-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-browser-usage-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":2.3409,"fromScenarioHhi":3716,"fromSharePercent":1.53,"fromSourceId":"statcounter-browser-us-2026","fromYear":2025,"hhiContributionChange":-0.2673,"isResidual":false,"marketName":"U.S. browser usage","marketSlug":"us-browser-usage","observedHhiChange":-108,"participantLabel":"Samsung Internet","participantSlug":"samsung-internet","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-113,"residualFirmAssumption":4,"scenarioHhiChange":-107,"shareChangePoints":-0.09,"toClassification":"highly_concentrated","toHhiContribution":2.0736,"toScenarioHhi":3608,"toSharePercent":1.44,"toSourceId":"statcounter-browser-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2023-2024-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":3586.8121,"fromScenarioHhi":5157,"fromSharePercent":59.89,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2023,"hhiContributionChange":-391.1712,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":-102,"participantLabel":"iOS","participantSlug":"ios","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-102,"residualFirmAssumption":4,"scenarioHhiChange":-102,"shareChangePoints":-3.36,"toClassification":"highly_concentrated","toHhiContribution":3195.6409,"toScenarioHhi":5055,"toSharePercent":56.53,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":1570.5369,"fromScenarioHhi":5157,"fromSharePercent":39.63,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2023,"hhiContributionChange":288.7975,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":-102,"participantLabel":"Android","participantSlug":"android","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-102,"residualFirmAssumption":4,"scenarioHhiChange":-102,"shareChangePoints":3.49,"toClassification":"highly_concentrated","toHhiContribution":1859.3344,"toScenarioHhi":5055,"toSharePercent":43.12,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2023-2024-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0784,"fromScenarioHhi":5157,"fromSharePercent":0.28,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2023,"hhiContributionChange":-0.0208,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":-102,"participantLabel":"Samsung","participantSlug":"samsung-mobile-os","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-102,"residualFirmAssumption":4,"scenarioHhiChange":-102,"shareChangePoints":-0.04,"toClassification":"highly_concentrated","toHhiContribution":0.0576,"toScenarioHhi":5055,"toSharePercent":0.24,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2023-2024-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0049,"fromScenarioHhi":5157,"fromSharePercent":0.07,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2023,"hhiContributionChange":-0.0045,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":-102,"participantLabel":"Windows Phone","participantSlug":"windows-phone","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-102,"residualFirmAssumption":4,"scenarioHhiChange":-102,"shareChangePoints":-0.05,"toClassification":"highly_concentrated","toHhiContribution":0.0004,"toScenarioHhi":5055,"toSharePercent":0.02,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2023-2024-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0016,"fromScenarioHhi":5157,"fromSharePercent":0.04,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2023,"hhiContributionChange":-0.0015,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":-102,"participantLabel":"SymbianOS","participantSlug":"symbianos","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-102,"residualFirmAssumption":4,"scenarioHhiChange":-102,"shareChangePoints":-0.03,"toClassification":"highly_concentrated","toHhiContribution":0.0001,"toScenarioHhi":5055,"toSharePercent":0.01,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2023-2024-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0002,"fromScenarioHhi":5157,"fromSharePercent":0.03,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2023,"hhiContributionChange":0.0002,"isResidual":true,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":-102,"participantLabel":"Other mobile operating systems","participantSlug":"other-mobile-operating-systems","participantStatus":"residual","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-102,"residualFirmAssumption":4,"scenarioHhiChange":-102,"shareChangePoints":0.01,"toClassification":"highly_concentrated","toHhiContribution":0.0004,"toScenarioHhi":5055,"toSharePercent":0.04,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2023-2024-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0001,"fromScenarioHhi":5157,"fromSharePercent":0.02,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2023,"hhiContributionChange":-0.0001,"isResidual":true,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":-102,"participantLabel":"Unknown mobile OS","participantSlug":"mobile-os-unknown","participantStatus":"residual","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-102,"residualFirmAssumption":4,"scenarioHhiChange":-102,"shareChangePoints":-0.01,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":5055,"toSharePercent":0.01,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2023-2024-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0001,"fromScenarioHhi":5157,"fromSharePercent":0.01,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2023,"hhiContributionChange":0,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":-102,"participantLabel":"KaiOS","participantSlug":"kaios","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-102,"residualFirmAssumption":4,"scenarioHhiChange":-102,"shareChangePoints":0,"toClassification":"highly_concentrated","toHhiContribution":0.0001,"toScenarioHhi":5055,"toSharePercent":0.01,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2023-2024-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0004,"fromScenarioHhi":5157,"fromSharePercent":0.02,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2023,"hhiContributionChange":0,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":-102,"participantLabel":"Linux","participantSlug":"mobile-linux","participantStatus":"continuing","possibleHhiChangeCeiling":-102,"possibleHhiChangeFloor":-102,"residualFirmAssumption":4,"scenarioHhiChange":-102,"shareChangePoints":0,"toClassification":"highly_concentrated","toHhiContribution":0.0004,"toScenarioHhi":5055,"toSharePercent":0.02,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2024-2025-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":3195.6409,"fromScenarioHhi":5055,"fromSharePercent":56.53,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2024,"hhiContributionChange":122.1191,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":39,"participantLabel":"iOS","participantSlug":"ios","participantStatus":"continuing","possibleHhiChangeCeiling":39,"possibleHhiChangeFloor":39,"residualFirmAssumption":4,"scenarioHhiChange":39,"shareChangePoints":1.07,"toClassification":"highly_concentrated","toHhiContribution":3317.76,"toScenarioHhi":5094,"toSharePercent":57.6,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":1859.3344,"fromScenarioHhi":5055,"fromSharePercent":43.12,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2024,"hhiContributionChange":-82.7119,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":39,"participantLabel":"Android","participantSlug":"android","participantStatus":"continuing","possibleHhiChangeCeiling":39,"possibleHhiChangeFloor":39,"residualFirmAssumption":4,"scenarioHhiChange":39,"shareChangePoints":-0.97,"toClassification":"highly_concentrated","toHhiContribution":1776.6225,"toScenarioHhi":5094,"toSharePercent":42.15,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0576,"fromScenarioHhi":5055,"fromSharePercent":0.24,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2024,"hhiContributionChange":-0.0176,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":39,"participantLabel":"Samsung","participantSlug":"samsung-mobile-os","participantStatus":"continuing","possibleHhiChangeCeiling":39,"possibleHhiChangeFloor":39,"residualFirmAssumption":4,"scenarioHhiChange":39,"shareChangePoints":-0.04,"toClassification":"highly_concentrated","toHhiContribution":0.04,"toScenarioHhi":5094,"toSharePercent":0.2,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2024-2025-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0004,"fromScenarioHhi":5055,"fromSharePercent":0.02,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2024,"hhiContributionChange":-0.0004,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":39,"participantLabel":"Windows Phone","participantSlug":"windows-phone","participantStatus":"exited","possibleHhiChangeCeiling":39,"possibleHhiChangeFloor":39,"residualFirmAssumption":4,"scenarioHhiChange":39,"shareChangePoints":-0.02,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":5094,"toSharePercent":0,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2024-2025-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0004,"fromScenarioHhi":5055,"fromSharePercent":0.02,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2024,"hhiContributionChange":-0.0003,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":39,"participantLabel":"Linux","participantSlug":"mobile-linux","participantStatus":"continuing","possibleHhiChangeCeiling":39,"possibleHhiChangeFloor":39,"residualFirmAssumption":4,"scenarioHhiChange":39,"shareChangePoints":-0.01,"toClassification":"highly_concentrated","toHhiContribution":0.0001,"toScenarioHhi":5094,"toSharePercent":0.01,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2024-2025-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0004,"fromScenarioHhi":5055,"fromSharePercent":0.04,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2024,"hhiContributionChange":-0.0003,"isResidual":true,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":39,"participantLabel":"Other mobile operating systems","participantSlug":"other-mobile-operating-systems","participantStatus":"residual","possibleHhiChangeCeiling":39,"possibleHhiChangeFloor":39,"residualFirmAssumption":4,"scenarioHhiChange":39,"shareChangePoints":-0.02,"toClassification":"highly_concentrated","toHhiContribution":0.0001,"toScenarioHhi":5094,"toSharePercent":0.02,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2024-2025-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0001,"fromScenarioHhi":5055,"fromSharePercent":0.01,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2024,"hhiContributionChange":-0.0001,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":39,"participantLabel":"SymbianOS","participantSlug":"symbianos","participantStatus":"exited","possibleHhiChangeCeiling":39,"possibleHhiChangeFloor":39,"residualFirmAssumption":4,"scenarioHhiChange":39,"shareChangePoints":-0.01,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":5094,"toSharePercent":0,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2024-2025-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0,"fromScenarioHhi":5055,"fromSharePercent":0.01,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2024,"hhiContributionChange":0,"isResidual":true,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":39,"participantLabel":"Unknown mobile OS","participantSlug":"mobile-os-unknown","participantStatus":"residual","possibleHhiChangeCeiling":39,"possibleHhiChangeFloor":39,"residualFirmAssumption":4,"scenarioHhiChange":39,"shareChangePoints":-0.01,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":5094,"toSharePercent":0,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2024-2025-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0001,"fromScenarioHhi":5055,"fromSharePercent":0.01,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2024,"hhiContributionChange":0,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":39,"participantLabel":"KaiOS","participantSlug":"kaios","participantStatus":"continuing","possibleHhiChangeCeiling":39,"possibleHhiChangeFloor":39,"residualFirmAssumption":4,"scenarioHhiChange":39,"shareChangePoints":0,"toClassification":"highly_concentrated","toHhiContribution":0.0001,"toScenarioHhi":5094,"toSharePercent":0.01,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2025-2026-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":3317.76,"fromScenarioHhi":5094,"fromSharePercent":57.6,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2025,"hhiContributionChange":661.3264,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":243,"participantLabel":"iOS","participantSlug":"ios","participantStatus":"continuing","possibleHhiChangeCeiling":243,"possibleHhiChangeFloor":243,"residualFirmAssumption":4,"scenarioHhiChange":243,"shareChangePoints":5.48,"toClassification":"highly_concentrated","toHhiContribution":3979.0864,"toScenarioHhi":5337,"toSharePercent":63.08,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":1776.6225,"fromScenarioHhi":5094,"fromSharePercent":42.15,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2025,"hhiContributionChange":-418.7,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":243,"participantLabel":"Android","participantSlug":"android","participantStatus":"continuing","possibleHhiChangeCeiling":243,"possibleHhiChangeFloor":243,"residualFirmAssumption":4,"scenarioHhiChange":243,"shareChangePoints":-5.3,"toClassification":"highly_concentrated","toHhiContribution":1357.9225,"toScenarioHhi":5337,"toSharePercent":36.85,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.04,"fromScenarioHhi":5094,"fromSharePercent":0.2,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2025,"hhiContributionChange":-0.0375,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":243,"participantLabel":"Samsung","participantSlug":"samsung-mobile-os","participantStatus":"continuing","possibleHhiChangeCeiling":243,"possibleHhiChangeFloor":243,"residualFirmAssumption":4,"scenarioHhiChange":243,"shareChangePoints":-0.15,"toClassification":"highly_concentrated","toHhiContribution":0.0025,"toScenarioHhi":5337,"toSharePercent":0.05,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2025-2026-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0001,"fromScenarioHhi":5094,"fromSharePercent":0.01,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2025,"hhiContributionChange":0.0003,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":243,"participantLabel":"KaiOS","participantSlug":"kaios","participantStatus":"continuing","possibleHhiChangeCeiling":243,"possibleHhiChangeFloor":243,"residualFirmAssumption":4,"scenarioHhiChange":243,"shareChangePoints":0.01,"toClassification":"highly_concentrated","toHhiContribution":0.0004,"toScenarioHhi":5337,"toSharePercent":0.02,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2025-2026-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0001,"fromScenarioHhi":5094,"fromSharePercent":0.01,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2025,"hhiContributionChange":-0.0001,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":243,"participantLabel":"Linux","participantSlug":"mobile-linux","participantStatus":"exited","possibleHhiChangeCeiling":243,"possibleHhiChangeFloor":243,"residualFirmAssumption":4,"scenarioHhiChange":243,"shareChangePoints":-0.01,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":5337,"toSharePercent":0,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2025-2026-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0001,"fromScenarioHhi":5094,"fromSharePercent":0.02,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2025,"hhiContributionChange":-0.0001,"isResidual":true,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":243,"participantLabel":"Other mobile operating systems","participantSlug":"other-mobile-operating-systems","participantStatus":"residual","possibleHhiChangeCeiling":243,"possibleHhiChangeFloor":243,"residualFirmAssumption":4,"scenarioHhiChange":243,"shareChangePoints":-0.02,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":5337,"toSharePercent":0,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2025-2026-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0,"fromScenarioHhi":5094,"fromSharePercent":0,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2025,"hhiContributionChange":0,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":243,"participantLabel":"SymbianOS","participantSlug":"symbianos","participantStatus":"continuing","possibleHhiChangeCeiling":243,"possibleHhiChangeFloor":243,"residualFirmAssumption":4,"scenarioHhiChange":243,"shareChangePoints":0,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":5337,"toSharePercent":0,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2025-2026-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0,"fromScenarioHhi":5094,"fromSharePercent":0,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2025,"hhiContributionChange":0,"isResidual":true,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":243,"participantLabel":"Unknown mobile OS","participantSlug":"mobile-os-unknown","participantStatus":"residual","possibleHhiChangeCeiling":243,"possibleHhiChangeFloor":243,"residualFirmAssumption":4,"scenarioHhiChange":243,"shareChangePoints":0,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":5337,"toSharePercent":0,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-mobile-operating-system-usage-2025-2026-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0,"fromScenarioHhi":5094,"fromSharePercent":0,"fromSourceId":"statcounter-mobile-os-us-2026","fromYear":2025,"hhiContributionChange":0,"isResidual":false,"marketName":"U.S. mobile operating-system web usage","marketSlug":"us-mobile-operating-system-usage","observedHhiChange":243,"participantLabel":"Windows Phone","participantSlug":"windows-phone","participantStatus":"continuing","possibleHhiChangeCeiling":243,"possibleHhiChangeFloor":243,"residualFirmAssumption":4,"scenarioHhiChange":243,"shareChangePoints":0,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":5337,"toSharePercent":0,"toSourceId":"statcounter-mobile-os-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2023-2024-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":2698.8025,"fromScenarioHhi":3393,"fromSharePercent":51.95,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2023,"hhiContributionChange":-586.4809,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":-555,"participantLabel":"Facebook","participantSlug":"facebook","participantStatus":"continuing","possibleHhiChangeCeiling":-555,"possibleHhiChangeFloor":-555,"residualFirmAssumption":4,"scenarioHhiChange":-555,"shareChangePoints":-5.99,"toClassification":"highly_concentrated","toHhiContribution":2112.3216,"toScenarioHhi":2838,"toSharePercent":45.96,"toSourceId":"statcounter-social-referral-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":131.3316,"fromScenarioHhi":3393,"fromSharePercent":11.46,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2023,"hhiContributionChange":216.864,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":-555,"participantLabel":"Pinterest","participantSlug":"pinterest","participantStatus":"continuing","possibleHhiChangeCeiling":-555,"possibleHhiChangeFloor":-555,"residualFirmAssumption":4,"scenarioHhiChange":-555,"shareChangePoints":7.2,"toClassification":"highly_concentrated","toHhiContribution":348.1956,"toScenarioHhi":2838,"toSharePercent":18.66,"toSourceId":"statcounter-social-referral-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2023-2024-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":379.0809,"fromScenarioHhi":3393,"fromSharePercent":19.47,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2023,"hhiContributionChange":-208.7784,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":-555,"participantLabel":"Twitter / X","participantSlug":"twitter-x","participantStatus":"continuing","possibleHhiChangeCeiling":-555,"possibleHhiChangeFloor":-555,"residualFirmAssumption":4,"scenarioHhiChange":-555,"shareChangePoints":-6.42,"toClassification":"highly_concentrated","toHhiContribution":170.3025,"toScenarioHhi":2838,"toSharePercent":13.05,"toSourceId":"statcounter-social-referral-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.9216,"fromScenarioHhi":3393,"fromSharePercent":0.96,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2023,"hhiContributionChange":21.4513,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":-555,"participantLabel":"Reddit","participantSlug":"reddit","participantStatus":"continuing","possibleHhiChangeCeiling":-555,"possibleHhiChangeFloor":-555,"residualFirmAssumption":4,"scenarioHhiChange":-555,"shareChangePoints":3.77,"toClassification":"highly_concentrated","toHhiContribution":22.3729,"toScenarioHhi":2838,"toSharePercent":4.73,"toSourceId":"statcounter-social-referral-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":3.4596,"fromScenarioHhi":3393,"fromSharePercent":1.86,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2023,"hhiContributionChange":4.606,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":-555,"participantLabel":"YouTube","participantSlug":"youtube","participantStatus":"continuing","possibleHhiChangeCeiling":-555,"possibleHhiChangeFloor":-555,"residualFirmAssumption":4,"scenarioHhiChange":-555,"shareChangePoints":0.98,"toClassification":"highly_concentrated","toHhiContribution":8.0656,"toScenarioHhi":2838,"toSharePercent":2.84,"toSourceId":"statcounter-social-referral-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2023-2024-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":179.0244,"fromScenarioHhi":3393,"fromSharePercent":13.38,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2023,"hhiContributionChange":-3.1968,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":-555,"participantLabel":"Instagram","participantSlug":"instagram","participantStatus":"continuing","possibleHhiChangeCeiling":-555,"possibleHhiChangeFloor":-555,"residualFirmAssumption":4,"scenarioHhiChange":-555,"shareChangePoints":-0.12,"toClassification":"highly_concentrated","toHhiContribution":175.8276,"toScenarioHhi":2838,"toSharePercent":13.26,"toSourceId":"statcounter-social-referral-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.2401,"fromScenarioHhi":3393,"fromSharePercent":0.49,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2023,"hhiContributionChange":0.5343,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":-555,"participantLabel":"LinkedIn","participantSlug":"linkedin","participantStatus":"continuing","possibleHhiChangeCeiling":-555,"possibleHhiChangeFloor":-555,"residualFirmAssumption":4,"scenarioHhiChange":-555,"shareChangePoints":0.39,"toClassification":"highly_concentrated","toHhiContribution":0.7744,"toScenarioHhi":2838,"toSharePercent":0.88,"toSourceId":"statcounter-social-referral-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0729,"fromScenarioHhi":3393,"fromSharePercent":0.27,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2023,"hhiContributionChange":0.0295,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":-555,"participantLabel":"Tumblr","participantSlug":"tumblr","participantStatus":"continuing","possibleHhiChangeCeiling":-555,"possibleHhiChangeFloor":-555,"residualFirmAssumption":4,"scenarioHhiChange":-555,"shareChangePoints":0.05,"toClassification":"highly_concentrated","toHhiContribution":0.1024,"toScenarioHhi":2838,"toSharePercent":0.32,"toSourceId":"statcounter-social-referral-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2023-2024-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0049,"fromScenarioHhi":3393,"fromSharePercent":0.07,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2023,"hhiContributionChange":0.0207,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":-555,"participantLabel":"Fark","participantSlug":"fark","participantStatus":"continuing","possibleHhiChangeCeiling":-555,"possibleHhiChangeFloor":-555,"residualFirmAssumption":4,"scenarioHhiChange":-555,"shareChangePoints":0.09,"toClassification":"highly_concentrated","toHhiContribution":0.0256,"toScenarioHhi":2838,"toSharePercent":0.16,"toSourceId":"statcounter-social-referral-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2023-2024-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0016,"fromScenarioHhi":3393,"fromSharePercent":0.04,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2023,"hhiContributionChange":0.0033,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":-555,"participantLabel":"Hacker News","participantSlug":"hacker-news","participantStatus":"continuing","possibleHhiChangeCeiling":-555,"possibleHhiChangeFloor":-555,"residualFirmAssumption":4,"scenarioHhiChange":-555,"shareChangePoints":0.03,"toClassification":"highly_concentrated","toHhiContribution":0.0049,"toScenarioHhi":2838,"toSharePercent":0.07,"toSourceId":"statcounter-social-referral-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2023-2024-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0001,"fromScenarioHhi":3393,"fromSharePercent":0.01,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2023,"hhiContributionChange":0.0008,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":-555,"participantLabel":"VKontakte","participantSlug":"vkontakte","participantStatus":"continuing","possibleHhiChangeCeiling":-555,"possibleHhiChangeFloor":-555,"residualFirmAssumption":4,"scenarioHhiChange":-555,"shareChangePoints":0.02,"toClassification":"highly_concentrated","toHhiContribution":0.0009,"toScenarioHhi":2838,"toSharePercent":0.03,"toSourceId":"statcounter-social-referral-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2023-2024-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0006,"fromScenarioHhi":3393,"fromSharePercent":0.05,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2023,"hhiContributionChange":-0.0004,"isResidual":true,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":-555,"participantLabel":"Other social referrals","participantSlug":"other-social-referrals","participantStatus":"residual","possibleHhiChangeCeiling":-555,"possibleHhiChangeFloor":-555,"residualFirmAssumption":4,"scenarioHhiChange":-555,"shareChangePoints":-0.02,"toClassification":"highly_concentrated","toHhiContribution":0.0002,"toScenarioHhi":2838,"toSharePercent":0.03,"toSourceId":"statcounter-social-referral-us-2026","toYear":2024,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2024-2025-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":2112.3216,"fromScenarioHhi":2838,"fromSharePercent":45.96,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2024,"hhiContributionChange":1188.1809,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":966,"participantLabel":"Facebook","participantSlug":"facebook","participantStatus":"continuing","possibleHhiChangeCeiling":966,"possibleHhiChangeFloor":966,"residualFirmAssumption":4,"scenarioHhiChange":966,"shareChangePoints":11.49,"toClassification":"highly_concentrated","toHhiContribution":3300.5025,"toScenarioHhi":3804,"toSharePercent":57.45,"toSourceId":"statcounter-social-referral-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":348.1956,"fromScenarioHhi":2838,"fromSharePercent":18.66,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2024,"hhiContributionChange":-126.7812,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":966,"participantLabel":"Pinterest","participantSlug":"pinterest","participantStatus":"continuing","possibleHhiChangeCeiling":966,"possibleHhiChangeFloor":966,"residualFirmAssumption":4,"scenarioHhiChange":966,"shareChangePoints":-3.78,"toClassification":"highly_concentrated","toHhiContribution":221.4144,"toScenarioHhi":3804,"toSharePercent":14.88,"toSourceId":"statcounter-social-referral-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":175.8276,"fromScenarioHhi":2838,"fromSharePercent":13.26,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2024,"hhiContributionChange":-101.5232,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":966,"participantLabel":"Instagram","participantSlug":"instagram","participantStatus":"continuing","possibleHhiChangeCeiling":966,"possibleHhiChangeFloor":966,"residualFirmAssumption":4,"scenarioHhiChange":966,"shareChangePoints":-4.64,"toClassification":"highly_concentrated","toHhiContribution":74.3044,"toScenarioHhi":3804,"toSharePercent":8.62,"toSourceId":"statcounter-social-referral-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2024-2025-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":170.3025,"fromScenarioHhi":2838,"fromSharePercent":13.05,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2024,"hhiContributionChange":29.6371,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":966,"participantLabel":"Twitter / X","participantSlug":"twitter-x","participantStatus":"continuing","possibleHhiChangeCeiling":966,"possibleHhiChangeFloor":966,"residualFirmAssumption":4,"scenarioHhiChange":966,"shareChangePoints":1.09,"toClassification":"highly_concentrated","toHhiContribution":199.9396,"toScenarioHhi":3804,"toSharePercent":14.14,"toSourceId":"statcounter-social-referral-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":22.3729,"fromScenarioHhi":2838,"fromSharePercent":4.73,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2024,"hhiContributionChange":-18.3729,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":966,"participantLabel":"Reddit","participantSlug":"reddit","participantStatus":"continuing","possibleHhiChangeCeiling":966,"possibleHhiChangeFloor":966,"residualFirmAssumption":4,"scenarioHhiChange":966,"shareChangePoints":-2.73,"toClassification":"highly_concentrated","toHhiContribution":4,"toScenarioHhi":3804,"toSharePercent":2,"toSourceId":"statcounter-social-referral-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":8.0656,"fromScenarioHhi":2838,"fromSharePercent":2.84,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2024,"hhiContributionChange":-5.1415,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":966,"participantLabel":"YouTube","participantSlug":"youtube","participantStatus":"continuing","possibleHhiChangeCeiling":966,"possibleHhiChangeFloor":966,"residualFirmAssumption":4,"scenarioHhiChange":966,"shareChangePoints":-1.13,"toClassification":"highly_concentrated","toHhiContribution":2.9241,"toScenarioHhi":3804,"toSharePercent":1.71,"toSourceId":"statcounter-social-referral-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2024-2025-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.7744,"fromScenarioHhi":2838,"fromSharePercent":0.88,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2024,"hhiContributionChange":-0.4719,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":966,"participantLabel":"LinkedIn","participantSlug":"linkedin","participantStatus":"continuing","possibleHhiChangeCeiling":966,"possibleHhiChangeFloor":966,"residualFirmAssumption":4,"scenarioHhiChange":966,"shareChangePoints":-0.33,"toClassification":"highly_concentrated","toHhiContribution":0.3025,"toScenarioHhi":3804,"toSharePercent":0.55,"toSourceId":"statcounter-social-referral-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2024-2025-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.1024,"fromScenarioHhi":2838,"fromSharePercent":0.32,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2024,"hhiContributionChange":0.0576,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":966,"participantLabel":"Tumblr","participantSlug":"tumblr","participantStatus":"continuing","possibleHhiChangeCeiling":966,"possibleHhiChangeFloor":966,"residualFirmAssumption":4,"scenarioHhiChange":966,"shareChangePoints":0.08,"toClassification":"highly_concentrated","toHhiContribution":0.16,"toScenarioHhi":3804,"toSharePercent":0.4,"toSourceId":"statcounter-social-referral-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2024-2025-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0256,"fromScenarioHhi":2838,"fromSharePercent":0.16,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2024,"hhiContributionChange":0.0068,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":966,"participantLabel":"Fark","participantSlug":"fark","participantStatus":"continuing","possibleHhiChangeCeiling":966,"possibleHhiChangeFloor":966,"residualFirmAssumption":4,"scenarioHhiChange":966,"shareChangePoints":0.02,"toClassification":"highly_concentrated","toHhiContribution":0.0324,"toScenarioHhi":3804,"toSharePercent":0.18,"toSourceId":"statcounter-social-referral-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2024-2025-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0009,"fromScenarioHhi":2838,"fromSharePercent":0.03,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2024,"hhiContributionChange":-0.0005,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":966,"participantLabel":"VKontakte","participantSlug":"vkontakte","participantStatus":"continuing","possibleHhiChangeCeiling":966,"possibleHhiChangeFloor":966,"residualFirmAssumption":4,"scenarioHhiChange":966,"shareChangePoints":-0.01,"toClassification":"highly_concentrated","toHhiContribution":0.0004,"toScenarioHhi":3804,"toSharePercent":0.02,"toSourceId":"statcounter-social-referral-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2024-2025-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0002,"fromScenarioHhi":2838,"fromSharePercent":0.03,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2024,"hhiContributionChange":-0.0002,"isResidual":true,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":966,"participantLabel":"Other social referrals","participantSlug":"other-social-referrals","participantStatus":"residual","possibleHhiChangeCeiling":966,"possibleHhiChangeFloor":966,"residualFirmAssumption":4,"scenarioHhiChange":966,"shareChangePoints":-0.03,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":3804,"toSharePercent":0,"toSourceId":"statcounter-social-referral-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2024-2025-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0049,"fromScenarioHhi":2838,"fromSharePercent":0.07,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2024,"hhiContributionChange":0,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":966,"participantLabel":"Hacker News","participantSlug":"hacker-news","participantStatus":"continuing","possibleHhiChangeCeiling":966,"possibleHhiChangeFloor":966,"residualFirmAssumption":4,"scenarioHhiChange":966,"shareChangePoints":0,"toClassification":"highly_concentrated","toHhiContribution":0.0049,"toScenarioHhi":3804,"toSharePercent":0.07,"toSourceId":"statcounter-social-referral-us-2026","toYear":2025,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2025-2026-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":3300.5025,"fromScenarioHhi":3804,"fromSharePercent":57.45,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2025,"hhiContributionChange":1452.2211,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":1191,"participantLabel":"Facebook","participantSlug":"facebook","participantStatus":"continuing","possibleHhiChangeCeiling":1192,"possibleHhiChangeFloor":1192,"residualFirmAssumption":4,"scenarioHhiChange":1192,"shareChangePoints":11.49,"toClassification":"highly_concentrated","toHhiContribution":4752.7236,"toScenarioHhi":4995,"toSharePercent":68.94,"toSourceId":"statcounter-social-referral-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":221.4144,"fromScenarioHhi":3804,"fromSharePercent":14.88,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2025,"hhiContributionChange":-164.7135,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":1191,"participantLabel":"Pinterest","participantSlug":"pinterest","participantStatus":"continuing","possibleHhiChangeCeiling":1192,"possibleHhiChangeFloor":1192,"residualFirmAssumption":4,"scenarioHhiChange":1192,"shareChangePoints":-7.35,"toClassification":"highly_concentrated","toHhiContribution":56.7009,"toScenarioHhi":4995,"toSharePercent":7.53,"toSourceId":"statcounter-social-referral-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":199.9396,"fromScenarioHhi":3804,"fromSharePercent":14.14,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2025,"hhiContributionChange":-64.6827,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":1191,"participantLabel":"Twitter / X","participantSlug":"twitter-x","participantStatus":"continuing","possibleHhiChangeCeiling":1192,"possibleHhiChangeFloor":1192,"residualFirmAssumption":4,"scenarioHhiChange":1192,"shareChangePoints":-2.51,"toClassification":"highly_concentrated","toHhiContribution":135.2569,"toScenarioHhi":4995,"toSharePercent":11.63,"toSourceId":"statcounter-social-referral-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":74.3044,"fromScenarioHhi":3804,"fromSharePercent":8.62,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2025,"hhiContributionChange":-34.866,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":1191,"participantLabel":"Instagram","participantSlug":"instagram","participantStatus":"continuing","possibleHhiChangeCeiling":1192,"possibleHhiChangeFloor":1192,"residualFirmAssumption":4,"scenarioHhiChange":1192,"shareChangePoints":-2.34,"toClassification":"highly_concentrated","toHhiContribution":39.4384,"toScenarioHhi":4995,"toSharePercent":6.28,"toSourceId":"statcounter-social-referral-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2025-2026-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":2.9241,"fromScenarioHhi":3804,"fromSharePercent":1.71,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2025,"hhiContributionChange":2.5048,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":1191,"participantLabel":"YouTube","participantSlug":"youtube","participantStatus":"continuing","possibleHhiChangeCeiling":1192,"possibleHhiChangeFloor":1192,"residualFirmAssumption":4,"scenarioHhiChange":1192,"shareChangePoints":0.62,"toClassification":"highly_concentrated","toHhiContribution":5.4289,"toScenarioHhi":4995,"toSharePercent":2.33,"toSourceId":"statcounter-social-referral-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2025-2026-4","deltaDirection":"increased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":4,"fromScenarioHhi":3804,"fromSharePercent":2,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2025,"hhiContributionChange":1.5225,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":1191,"participantLabel":"Reddit","participantSlug":"reddit","participantStatus":"continuing","possibleHhiChangeCeiling":1192,"possibleHhiChangeFloor":1192,"residualFirmAssumption":4,"scenarioHhiChange":1192,"shareChangePoints":0.35,"toClassification":"highly_concentrated","toHhiContribution":5.5225,"toScenarioHhi":4995,"toSharePercent":2.35,"toSourceId":"statcounter-social-referral-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.3025,"fromScenarioHhi":3804,"fromSharePercent":0.55,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2025,"hhiContributionChange":-0.1425,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":1191,"participantLabel":"LinkedIn","participantSlug":"linkedin","participantStatus":"continuing","possibleHhiChangeCeiling":1192,"possibleHhiChangeFloor":1192,"residualFirmAssumption":4,"scenarioHhiChange":1192,"shareChangePoints":-0.15,"toClassification":"highly_concentrated","toHhiContribution":0.16,"toScenarioHhi":4995,"toSharePercent":0.4,"toSourceId":"statcounter-social-referral-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.16,"fromScenarioHhi":3804,"fromSharePercent":0.4,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2025,"hhiContributionChange":-0.0759,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":1191,"participantLabel":"Tumblr","participantSlug":"tumblr","participantStatus":"continuing","possibleHhiChangeCeiling":1192,"possibleHhiChangeFloor":1192,"residualFirmAssumption":4,"scenarioHhiChange":1192,"shareChangePoints":-0.11,"toClassification":"highly_concentrated","toHhiContribution":0.0841,"toScenarioHhi":4995,"toSharePercent":0.29,"toSourceId":"statcounter-social-referral-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2025-2026-4","deltaDirection":"decreased","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0324,"fromScenarioHhi":3804,"fromSharePercent":0.18,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2025,"hhiContributionChange":-0.0068,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":1191,"participantLabel":"Fark","participantSlug":"fark","participantStatus":"continuing","possibleHhiChangeCeiling":1192,"possibleHhiChangeFloor":1192,"residualFirmAssumption":4,"scenarioHhiChange":1192,"shareChangePoints":-0.02,"toClassification":"highly_concentrated","toHhiContribution":0.0256,"toScenarioHhi":4995,"toSharePercent":0.16,"toSourceId":"statcounter-social-referral-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2025-2026-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0049,"fromScenarioHhi":3804,"fromSharePercent":0.07,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2025,"hhiContributionChange":0.0032,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":1191,"participantLabel":"Hacker News","participantSlug":"hacker-news","participantStatus":"continuing","possibleHhiChangeCeiling":1192,"possibleHhiChangeFloor":1192,"residualFirmAssumption":4,"scenarioHhiChange":1192,"shareChangePoints":0.02,"toClassification":"highly_concentrated","toHhiContribution":0.0081,"toScenarioHhi":4995,"toSharePercent":0.09,"toSourceId":"statcounter-social-referral-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2025-2026-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0.0004,"fromScenarioHhi":3804,"fromSharePercent":0.02,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2025,"hhiContributionChange":-0.0004,"isResidual":false,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":1191,"participantLabel":"VKontakte","participantSlug":"vkontakte","participantStatus":"exited","possibleHhiChangeCeiling":1192,"possibleHhiChangeFloor":1192,"residualFirmAssumption":4,"scenarioHhiChange":1192,"shareChangePoints":-0.02,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":4995,"toSharePercent":0,"toSourceId":"statcounter-social-referral-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."},{"comparisonId":"us-social-media-referral-traffic-2025-2026-4","deltaDirection":"unchanged","framework":"guidelines_2023","fromClassification":"highly_concentrated","fromHhiContribution":0,"fromScenarioHhi":3804,"fromSharePercent":0,"fromSourceId":"statcounter-social-referral-us-2026","fromYear":2025,"hhiContributionChange":0,"isResidual":true,"marketName":"U.S. social-media referral traffic","marketSlug":"us-social-media-referral-traffic","observedHhiChange":1191,"participantLabel":"Other social referrals","participantSlug":"other-social-referrals","participantStatus":"residual","possibleHhiChangeCeiling":1192,"possibleHhiChangeFloor":1192,"residualFirmAssumption":4,"scenarioHhiChange":1192,"shareChangePoints":0,"toClassification":"highly_concentrated","toHhiContribution":0,"toScenarioHhi":4995,"toSharePercent":0,"toSourceId":"statcounter-social-referral-us-2026","toYear":2026,"guardrail":"HHI contribution changes are descriptive share-squared arithmetic, not causal estimates. A participant's contribution can rise or fall because its observed share changed; the decomposition does not establish conduct, competitive effects, liability, or consumer harm. Aggregate residual categories remain sensitivity assumptions rather than observed firm distributions."}]}