In a dramatic courtroom revelation, Mozilla’s Chief Financial Officer Eric Muhlheim warned that Firefox could be forced out of business if the U.S. Department of Justice’s (DOJ) proposed remedies against Google’s search monopoly are fully implemented. The testimony, delivered during Google’s antitrust trial, sheds light on the hidden risks behind efforts to dismantle Big Tech dominance.
The DOJ vs. Google: What’s at Stake?
The Justice Department aims to break Google’s grip on the search engine market by banning it from paying to be the default search provider on third-party browsers like Firefox. The proposal also includes a potential forced sale of Google Chrome and a requirement to syndicate search results to competitors.
The court has already determined that Google holds an illegal monopoly — a result of exclusionary deals that prevent rival search engines from scaling and gaining distribution. However, Mozilla, which relies heavily on Google’s financial support, fears that cutting this lifeline could be catastrophic.
Firefox’s Dependency on Google Runs Deep
According to Muhlheim, around 90% of Mozilla’s revenue comes from Firefox, and 85% of that is directly tied to its deal with Google. Without that revenue, Mozilla would be forced to enact deep company-wide cuts and scale back its investment in Firefox, ultimately risking a “downward spiral” that could end the browser’s existence.
The implication is stark: ending Google’s default search deals could unintentionally eliminate one of Chrome’s main competitors, further consolidating market power — the very thing the DOJ hopes to prevent.
No Easy Replacement for Google’s Dollars
Mozilla has explored alternatives like Microsoft’s Bing. However, Muhlheim testified that without Google bidding, the revenue from a potential Bing deal would likely be much lower. Furthermore, Bing’s monetization is far less efficient than Google’s, meaning Mozilla would struggle to maintain its current operations.
In fact, Mozilla once ran a study between 2021 and 2022 where it quietly switched some users’ default search engine from Google to Bing. The result? Revenue dropped significantly — a warning sign for what may come if the DOJ enforces its plan.
A Precarious Precedent: Remember the Yahoo Switch?
This wouldn’t be the first time Firefox suffered from a default engine change. Between 2014 and 2017, Mozilla made Yahoo the default search engine — a move that backfired. Users disliked the experience so much that many abandoned Firefox altogether, a risk Mozilla fears repeating.
The Broader Impact: Open Source and Internet Diversity at Risk
Beyond the browser, Mozilla’s nonprofit efforts — such as funding open-source web tools and researching how AI can help fight climate change — also depend on the Firefox revenue stream. Muhlheim emphasized that Gecko, Firefox’s browser engine, is the only major engine not controlled by Big Tech. Losing it could further erode diversity and innovation in the web ecosystem.
Can a Competitive Market Save Firefox?
The DOJ argues that its actions would create a healthier search market with more viable players that could compete for Firefox’s default engine spot. But Mozilla warns that such a future is distant and uncertain — and the damage to Firefox could occur long before those benefits materialize.
As Muhlheim bluntly put it: “We would be really struggling to stay alive.”
