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Mozilla CFO Warns Antitrust Remedies Could Doom Firefox

 |  May 4, 2025

A top executive from Mozilla warned on Friday that the U.S. Justice Department’s proposed remedies in the ongoing antitrust case against Google could devastate Firefox and threaten the nonprofit’s future, due to its heavy reliance on revenue from its search deal with Google.

Testifying at the close of the second week of a closely watched antitrust trial, Mozilla’s Chief Financial Officer Eric Muhlheim told U.S. District Judge Amit Mehta that the Justice Department’s suggestions — including banning default search engine deals and forcing Google to divest its Chrome browser — would likely lead to severe budget cuts at Mozilla, putting the long-term viability of Firefox at risk.

Per Courthouse News, the government has proposed sweeping remedies intended to roll back what it views as Google’s longstanding monopoly over online search and search advertising. Among the proposals: prohibit exclusive agreements that make Google the default on browsers like Safari and Firefox, release extensive user data to help rival search engines compete, and potentially separate Chrome or Android from the rest of Google.

While Mozilla operates Firefox in direct competition with Chrome, Muhlheim emphasized that the proposed changes would hurt more than help. According to Courthouse News, he testified that about 90% of Mozilla’s revenue comes from Firefox, and approximately 85% of that total stems from its current arrangement with Google. If default status payments were eliminated, Mozilla would be forced to implement major cutbacks.

“It’s very frightening,” Muhlheim told the court, explaining that such financial losses could cause a “downward spiral” of reduced investment, user attrition, and ultimately, the potential demise of Firefox altogether.

The stakes are high not only for Mozilla, but for the broader web ecosystem. Muhlheim noted that Mozilla’s Gecko browser engine is the only one maintained by a nonprofit and not under the control of tech giants like Apple or Google. Losing Gecko, he said, could limit internet diversity and undermine the open-source values that have defined Mozilla since its inception.

During questioning, he also acknowledged that while Mozilla’s dependency on Google isn’t ideal, alternative search engines like Microsoft’s Bing haven’t offered deals with similar value. According to Courthouse News, he explained that Bing’s ad monetization isn’t as effective, making it a less attractive partner.

In contrast to the Justice Department’s broad remedies, Google has urged Judge Mehta to consider a more limited approach. Its proposal would allow rival search engines to bid for default placement on a per-device, per-year basis, potentially rotating the default engine across different platforms like iPads, iPhones, or Macs. Google also suggested lifting requirements that Android devices come with Chrome and Google Search pre-installed.

Google maintains that the government’s recommendations would stifle competition and harm consumer choice — a view echoed in part by Muhlheim, who expressed concern that Mozilla would be unable to support its mission without the financial lifeline Google provides.

As the trial moves forward, Judge Mehta faces the difficult task of crafting remedies that promote competition without dismantling the infrastructure of smaller players that rely on Google’s dominance to survive.

Source: Courthouse News