Antitrust Radar
Merger activity observatory

Scenario analysis / observed shares

Merger structure lab

Calculate a hypothetical concentration change from two published participant shares. This is an arithmetic screen, not a claim that a transaction exists or a legal conclusion.

Live scenarioChrome+Safari
Delta HHI+3,187.91Post HHI6,799.91
Eligible markets
6
Observed firm-level shares
Observed periods
18
Definition-matched snapshots
Complete HHI screens
17
Baseline and post-merger HHI
Share observations
136
Named, source-labeled rows
Scenario layer

Market, observed period, and two source-labeled participants can change.

Evidence layer

Published shares, baseline HHI, source status, confidence, and definition remain fixed.

Interpretation layer

Numeric conditions are screening inputs, never a standalone liability or outcome claim.

Observed-share scenario

Structure screen

BrowsersUnited StatesPublic proxyUsage shares97.89%named share coverageComplete HHIMedium confidence

Software / 2026

Chrome + Safari

2 x 50.03% x 31.86% = 3187.91 HHI points
Numeric condition crossedThe selected shares cross both published Guideline 1 numeric paths.
Baseline HHI
3,612
2026 published anchor
Delta HHI
+3,187.91
Exact 2ab arithmetic
Post-merger HHI
6,799.91
Published baseline + delta
Merged share
81.89%
50.03% + 31.86%
Participant geometryObserved shares, combined only for this scenario
Observed2026
CombinedScenario
Chrome + Safari81.89%Edge8.12%Firefox3.75%Brave2.69%Other browsers2.11%Samsung Internet1.44%
Guideline 1 numeric pathsOfficial reference
Guideline 1 HHI threshold planePost-merger HHI is plotted horizontally and the merger-related HHI increase vertically. The published numeric path is above 1,800 post-merger HHI and above 100 delta HHI. The selected scenario plots at post-merger HHI 6799.91 and delta HHI 3187.91.02,5005,0007,50010,00001,7503,500HHI 1,800Delta 100Post-merger HHIDelta HHI
Merged-firm share path81.89%

Share above 30% and delta HHI above 100: crossed

Evidence contractOpen market profile

The scenario inherits this published boundary

Product
All-platform browser usage
Geography
United States
Measurement
StatCounter browser page-view usage share
Denominator
Observed U.S. browser usage in each reported monthly snapshot

IncludedNamed browsers and a residual Other category that closes the public share table to 100 percent

ExcludedUnique browser users, browser revenue, operating-system share, and tying conduct

LimitationPage-view usage is a public web-analytics proxy rather than a count of browser users or a revenue measure.

Reusable scenario packet

Carry the exact inputs into research

Antitrust Radar, Merger Structure Lab: Chrome + Safari in U.S. browser usage (2026); observed shares 50.03% and 31.86%; ΔHHI 3187.91; post-merger HHI 6799.91.
JSONCSV

Source custody

Browser market share in United States of America, April 2023-April 2026StatCounter Global Stats2023 Merger Guidelines, Guideline 1U.S. Department of Justice and Federal Trade Commission / December 18, 2023

01This tool combines two observed shares as a research scenario. It does not report an actual transaction, define a legal market, or predict an agency or court outcome.

02The calculation inherits the published public proxy boundary, United States, measurement basis, denominator, and source limitations shown below.

03The post-merger HHI adds the exact share-based delta to the published, rounded baseline HHI; small rounding differences can remain.

04Guideline 1 concentration arithmetic is one screening framework. The Merger Guidelines identify additional fact-specific theories, evidence, and rebuttal considerations.

The JSON and CSV packets preserve the selected shares, arithmetic, thresholds, evidence status, definition contract, sources, citation, and guardrails.

Merger Structure Lab | Antitrust Radar