Thirty years ago, US v. Microsoft, the last big US antitrust fight against a dominant software platform, ended without a breakup. The same question is back over Chrome, which the DOJ argues has become a distribution chokepoint for Google Search, inside the full browser wars 2.0 overview.
Here is why divestiture is on the table, how default deals loop, and which browser engines you should build and test for. By the end, you will see the case the way regulators do: the visible story is the Chrome divestiture, but the real structure is default distribution and engine control one layer down.
1. Why Is the DOJ Pursuing Chrome Divestiture From Google?
The DOJ treats Chrome as a distribution chokepoint. It carries roughly 35 percent of Google’s queries, making the browser a self-preferencing funnel for search.
Default deals and self-preferencing raise switching costs, and behavioural rules have a historically mixed record. So the DOJ argued for structural separation of Chrome and Android rather than policing the incentive.
Judge Amit Mehta’s August 2024 liability ruling led to a September 2025 remedy order, then a December 2025 Final Judgment that declined the divestitures and imposed behavioural remedies instead. The European Commission fined Google €890 million under the Digital Markets Act, and Swiss regulators have opened their own probe into whether Android’s setup changes hide competing search engines. It follows the shifting market share this case builds on.
2. How Do Google’s Default Search Placement Deals Reinforce Chrome’s Dominance?
The mechanism is a payments loop. Google pays distribution partners roughly $26 billion a year to be the default, with a large share going to Apple for Safari; Mozilla, OEMs and carriers take the rest.
The payments are conditioned on default status, and default inertia means most users never change a default, so each placement compounds share. Judge Mehta described an ecosystem that is resistant to change.
Default drives queries, queries drive ad revenue, and ad revenue lets Google outbid rivals for the next contract. Salop’s proposed payment ban would decouple payment from default status, paying distributors per search regardless of engine. The court’s injunction is narrower, part of where the market share is moving.
3. What Did Judge Amit Mehta Actually Rule, and Why Did the Court Reject a Chrome Breakup?
In August 2024, Judge Mehta ruled that Google is a monopolist in general search and search text advertising under Sherman Act §2: Google is a monopolist, and it has acted as one to maintain its monopoly.
In December 2025 he declined the Chrome and Android divestitures and ordered behavioural remedies instead: injunctions on exclusive deals, search-index and user-data sharing, and syndication licences for results and text ads. A Technical Committee sets the licence terms and Qualified Competitor criteria, and the remedies live on those terms.
The breakup scepticism draws on US v. Microsoft and Chromium‘s maintenance. Judge Mehta noted very few could demonstrate they could maintain the project behind so many browsers. The judgment is under cross-appeal, so divestiture remains live, as the antitrust and lock-in mechanics explain.
4. Why Do Browser Advocates Argue That “Browsers Are App Stores”?
The split outcome pushes the debate one layer down, from who owns the browser to what the browser controls. Modern browsers gate web-app installation, permissions, push messaging and payment surfaces, the same distribution function that a native app store controls. So advocates argue that browsers are stores filled with interoperable software. Whoever controls the default browser and its engine controls what web apps reach users.
PWAs are the technical proof. They install to a home screen and update without store review, making a capable browser an alternative to an app store. For your own delivery decisions, PWA versus native is a distribution-control question: PWAs bypass store review and shorten update cadence, while native apps offer deeper OS integration at higher platform risk.
On iOS, Apple’s WebKit-only rule keeps third-party engines blocked, so Apple remains the sole distributor of web-app capability. The enterprise browser comparison lays out the alternatives.
5. How Does Browser Engine Choice (Blink, WebKit, Gecko) Affect Competition and Lock-In?
Three engines render virtually every session. Blink (Chromium) powers Chrome, Edge, Opera and Brave; WebKit powers Safari on iOS; Gecko powers Firefox. Blink alone powers more than three quarters of every web session, and Blink plus WebKit hold 97.2 percent.
Choosing between Chromium shells offers little engine competition; the shared codebase is a compatibility win and a concentration risk. Engine divergence raises the cost of testing across engines, which entrenches whatever engine the default browser ships.
For your team, the practical guidance is to build for Blink, test on WebKit, and verify on Gecko, then weight your test matrix by audience share, engine coverage and regulatory exposure rather than an exhaustive device grid. The engine disruption piece covers the extension and AI disruptions accelerating this split.
6. Structural Breakup vs Behavioural Remedies: Which Better Restores Browser and Search Competition?
Neither fix is sufficient. Divestiture removes Google’s incentive to preference its own search, but leaves Chromium maintenance and funding unresolved. Behavioural remedies target entry barriers directly, but their record is weak and incumbents route around conduct rules.
The US Sherman Act is ex-post, while the EU Digital Markets Act is ex-ante. The DMA’s choice screens delivered share gains for smaller browsers, but engine-level concentration has barely moved.
The test is whether a remedy changes engine-level concentration and default switching. The forward risk is that AI surfaces like AI Overviews and assistants become the next default-deal channel, as the privacy and AI forces compounding this pressure make clear.
The fight to unlock browsers is about control of the default and the rendering engine. Neither breakup nor behavioural remedies is clearly enough on its own: divestiture fixes the incentive but leaves Chromium funding open, and conduct rules are only as good as their enforcement.
The metric that matters is engine-level concentration and default switching, not brand share. And the forward risk is already forming: AI surfaces like AI Overviews and assistants could become the next default-deal distribution channel before the appeals finish. For your team, treat engine choice, PWA delivery and the test matrix as regulatory-exposed decisions. The platform risk is live now.
Frequently Asked Questions
Will Chrome still work if Google is forced to sell it?
Yes. Divestiture would change who owns Chrome, not whether the browser keeps working for users. Tabs, extensions, saved settings and security updates would continue because the product itself is not being shut down. What changes is the incentive structure: a separated Chrome would no longer be owned by the same company that profits from Google Search preferences.
What is a default search deal, exactly?
A default search deal is a payment contract that makes one search engine the pre-set option in a browser or on a device. Google pays Apple, Mozilla, OEMs and carriers roughly $26B a year to hold that default, which means most users never choose another engine. The placement matters because default inertia keeps query volume flowing to whichever engine holds the contract.
What is the difference between a browser and a browser engine?
A browser is the application you open, such as Chrome, Safari or Firefox. The engine is the underlying code that renders the page: Blink powers Chrome and Edge, WebKit powers Safari, and Gecko powers Firefox. Several brands can share one engine, which is why browser-brand diversity can hide real engine concentration, and why the chokepoint sits one layer down.
Does this case affect Safari and Firefox as well?
Yes, indirectly. Safari and Firefox depend on the same default-search payments the court has now constrained, so their funding and distribution could shift. Firefox runs on Gecko, which makes it the main non-Blink, non-WebKit engine, and Safari’s WebKit-only rule on iOS keeps Apple in control of web app capability. The remedy’s effects therefore reach far beyond Chrome.
Who would fund Chromium if Google sold Chrome?
That is the unresolved cost of a breakup. Chromium is open source but overwhelmingly maintained and funded by Google engineers, so divestiture raises real questions about who pays for its upkeep. The court cited this maintenance risk as one reason it declined structural separation. Without a clear funding model, a split could slow security patches and standards work across every Blink-based browser.
Are the EU’s browser choice screens actually working?
Partially. The Digital Markets Act’s choice screens did deliver share gains for smaller browsers, which is real progress. But after two years they have not produced a third-party browser engine on iOS, where WebKit-only rules keep the gate closed in practice. So choice screens move users between brands, but they have not yet cracked engine-level concentration, which is the metric that matters.
What are Progressive Web Apps, and why do they matter here?
Progressive Web Apps, or PWAs, are standards-based web apps that install to a home screen and update without app-store review. They matter because they are the proof that a capable browser can act as a credible alternative to a native app store. Whoever controls the default browser and its engine controls that installation path, which is exactly the gatekeeper problem at the centre of the case.
Can Google still pay Apple to stay the default in Safari?
The December 2025 Final Judgment restricts the exclusive-deal mechanics rather than banning all payments outright. Google can still pay, but the court’s injunctions and syndication terms are designed to stop payment from being conditioned on default status. The open question is whether a Salop-style payment ban (paying per search regardless of engine) gets imposed on appeal.
What does self-preferencing mean?
Self-preferencing means a platform ranking or promoting its own products over rivals. Here, the DOJ argues Chrome funnels roughly 35% of Google Search queries back to Google, acting as a self-preferencing funnel for the search monopoly rather than a neutral competitor. That incentive, not the browser itself, is why regulators wanted separation of Chrome from Search.
Does the ruling affect Android phones too?
Yes. The DOJ had also sought divestiture of Android, and while the court declined that too, the behavioural remedies still touch mobile distribution through restrictions on OEM and carrier default deals. Android is where pre-installation and default inertia hit hardest, so the constraints reshape how search reaches phone users even without a forced sale.
What should web development teams change now?
Teams should treat engine choice, PWA delivery and the cross-browser test matrix as regulatory-exposed decisions. Build for Blink, validate across WebKit and Gecko, and weight the matrix by audience share, engine coverage and regulatory exposure rather than an exhaustive device grid. The unresolved remedy question does not wait for the appeals to finish; it is already a live platform risk.
Is it true there are only three browser engines?
Effectively, yes. Blink, WebKit and Gecko render virtually every web session today, even though dozens of browser brands exist. Blink alone covers roughly three-quarters of rendered sessions across Chrome, Edge, Opera, Brave and others. That concentration is the real lock-in point beneath the brand layer, and it is what any remedy must ultimately change.
