Firefox may cease to exist if the court implements all of the Justice Department’s proposals to limit Google’s search monopoly, the head of Mozilla, the company that owns the browser, said on Friday. “It’s very frightening,” said Mozilla CFO Eric Mulheim.
The DOJ wants to prohibit Google from paying to be the default search engine in third-party browsers, including Firefox, among a long list of other proposals, including forcing it to sell its own Chrome browser and requiring Google to syndicate search results with competitors. The court has already ruled that Google has an illegal monopoly in search, thanks in part to exclusive agreements that make it the default engine in browsers and phones, denying competitors room to distribute their search engines and scale. But while Firefox – whose CFO is testifying as Google presents its defense – competes directly with Chrome, he warns that losing lucrative default payments from Google could threaten its existence.
According to Mulheim, the CFO of Mozilla’s commercial division, Firefox generates about 90 percent of the company’s revenue, which in turn helps fund the nonprofit Mozilla Foundation. He added that about 85 percent of that revenue comes from the Google deal.
Losing this revenue at the same time would mean that Mozilla would be forced to make “significant cuts across the company,” Mulheim testified, and warned of a “downward spiral” that could occur if the company had to cut back on investment in Firefox product development, making it less attractive to users. Such a spiral, he said, could “put Firefox out of business.” It could also mean less money for nonprofit efforts such as open-source web tools and evaluating how AI can help fight climate change.
Ironically, Muhlheim suggested that this could perpetuate the very market dominance the court is trying to correct. According to him, the Gecko browser engine underlying Firefox is “the only browser engine that is not owned by a large tech company but by a non-profit organization.” The other two are Google’s open-source Chromium and Apple’s WebKit. Mozilla developed Gecko to prevent fears that Microsoft would control all protocols on the Internet, Muhlheim testified, and the creation of Gecko helped ensure that different browsers were compatible so that Internet access was not controlled by one company. (Unlike many other companies involved in the Google lawsuit, Firefox has not expressed interest in acquiring Chrome.)
Replacing Google’s revenue isn’t as simple as signing a deal with another search provider or a non-exclusive agreement with Google, says Mulheim. Mozilla has discussed with Microsoft the possibility of Bing taking over as the default, but Mulheim warns that if Google fails to bid, the share of revenue Mozilla can negotiate will likely decrease. In addition, Mozilla has found that Bing does not monetize traffic as effectively as Google does today.
In a presentation to Mozilla’s board of directors in December 2024, which was shown in court, the company warned that the loss of payments from Google posed a “significant threat to Mozilla’s viability with limited mitigation options.” In 2021-2022, the company conducted a study to see what would happen if it quietly switched Firefox users’ default search engines from Google to Bing and found that users who switched to Bing generated less revenue for Mozilla – a finding that Mulheim said demonstrates what could happen if all of its users switched to Bing.
Mozilla has previously tried to change the default search engines for all users, and it was not successful. Between 2014 and 2017, the company made Yahoo the default search engine in its browser, and found that users disliked it so much that they switched to another browser altogether.
If the DOJ’s other proposals work as it hopes, they would theoretically create many more quality search engines that could compete with Firefox for the default spot and take over the share of revenue that Google currently pays it. But Muhlheim says this is likely to take so long that Mozilla will have to significantly cut costs and change its strategy, “waiting for a hypothetical future in which this happens.” In the meantime, he said, “we will fight to stay alive.”
Under cross-examination by the Justice Department, Muhlheim admitted that it would be better not to rely on one customer for the vast majority of its revenue, regardless of the court’s decision in the case. And he agreed that another browser company, Opera, has already managed to make more money from in-browser advertising than from deals with search engines. But while this could be a potential route to diversifying Firefox’s revenue, he added, scaling such a business may look different for Firefox, in part because of the privacy approach the company takes to its products.
Mozilla supports opt-in screens for browsers on phones and desktops, the DOJ noted, and this would be directly beneficial to it. But it does not support a choice screen for users to select a default search engine in the browser. According to Muhlheim, Firefox regularly reminds users that they have multiple search options – “there are a thousand different search points in the browser,” as he testified. “Choice is a core value for us, but context matters,” he added in cross-examination. “The best way to get to choice is not always a choice screen.”
Judge Amit Mehta asked Mulheim if he agreed that it would be beneficial for Mozilla if there was at least one other company that matched Google in terms of quality and ability to monetize search. “If we were suddenly in that world,” Mulheim replied, “it would be a world that would be better for Mozilla.
