Norwegian browser developer Opera (OPRA.O) has filed a formal antitrust complaint with Brazil’s competition watchdog CADE, accusing U.S. tech giant Microsoft (MSFT.O) of unfairly favoring its Edge browser on Windows devices. The complaint marks a continuation of the long-standing rivalry between the two companies over browser market dominance.
Opera claims that Microsoft gives Edge an unfair competitive edge by pre-installing it as the default browser on Windows computers, effectively sidelining competitors. The complaint alleges that this practice prevents users from easily switching to alternative browsers and restricts competitors from accessing key distribution channels.
“Microsoft thwarts browser competition on Windows at every turn,” said Aaron McParlan, Opera’s general counsel. “First, browsers like Opera are locked out of important preinstallation opportunities. And then Microsoft frustrates users’ ability to download and use alternative browsers.”
Opera, currently the third-most popular desktop browser in Brazil with 6.78% market share (StatCounter, June data), trails behind Microsoft Edge at 11.52%, while Google Chrome dominates with a 75% share.
The company also accused Microsoft of leveraging anti-competitive tactics, including financial incentives to PC manufacturers for exclusive Edge pre-installation and employing so-called “dark patterns”—design tricks that discourage users from switching to rival browsers.
This isn’t Opera’s first clash with Microsoft. In 2007, it filed a complaint with the European Commission over Microsoft bundling Internet Explorer with Windows, which resulted in a €561 million ($648 million) antitrust fine for Microsoft. Opera also challenged the EU Commission in court last year for allegedly exempting Edge from provisions of the Digital Markets Act.
Opera is now urging CADE to launch a thorough investigation and impose corrective measures to ensure fair browser competition on Windows platforms. Microsoft has yet to issue a response.
