• by Wendy Davis , June 1, 2026

Mozilla is urging a federal appeals court to reverse one of the key findings made by U.S. District Court Amit Mehta, who ruled that Google violated antitrust law by monopolizing search.

In 2024, Mehta concluded after a 10-week trial that Google's position as the default search engine on Mozilla's Firefox and Apple's Safari, and on Android devices, enabled Google to maintain a monopoly in two markets -- general search services, and search text ads.

Mehta characterized the default search arrangements with Mozilla and Safari as "exclusive," writing that the agreements "establish Google as the out-of-the-box default search engine." Mehta went on to hold that Google violated antitrust law by engaging in exclusive agreements that had anticompetitive effects in the market.

Mozilla now argues in a friend-of-the-court brief that Mehta wrongly determined its search deal with Google was "exclusive."

"Mozilla ensured that the agreement never contained any express or implicit exclusivity requirement," the company argues in its brief, filed late last week with the D.C. Circuit Court of Appeals.

The company adds that evidence in the case "irrefutably establishes that Mozilla selected Google as the Firefox search default based on product quality and user preference."

Mozilla says its brief is "in support of neither party and reversal" -- meaning it is only contesting Mehta's conclusion that its deal with Google was an exclusive contract, and isn't taking a position on the larger question of whether Google's other deals violated antitrust law.

Among other arguments, Mozilla says in the new filing that its former search deal with Yahoo -- which involved installing Yahoo as the default search engine for Firefox from 2014 to 2017 -- proves that "non-default search engines can compete for and win significant percentages of Firefox search traffic."

Mozilla specifically points to statements by its chief financial officer, who testified at trial that Firefox users "did not like the Yahoo Search experience," and shifted from the default to another search engine.

Google recently appealed Mehta's ruling, arguing in papers filed last month that both Mozilla and Apple chose Google as the default search engine "for the procompetitive reason of improving their users’ experience."

The Justice Department and states are expected to file papers with the D.C. Circuit in July.