Opera Files Antitrust Complaint Against Microsoft in Brazil

In a significant move underscoring ongoing tensions between tech giants, the Norwegian browser maker Opera has lodged a formal complaint against Microsoft with Brazil's antitrust authority, CADE. The complaint, submitted on July 25, 2025, alleges that Microsoft's Edge browser enjoys an unfair competitive advantage due to its pre-installation as the default browser on Windows devices, effectively stifling competition from alternative browsers. This complaint echoes past grievances, notably Opera's previous allegations to the European Commission regarding Microsoft's bundling of Internet Explorer with its Windows operating system, which resulted in a hefty fine of €561 million (approximately $648 million) in 2013.

According to Aaron McParlan, General Counsel of Opera, the company's latest allegations highlight Microsoft's systematic efforts to undermine competition in the browser market. "Microsoft thwarts browser competition on Windows at every turn. First, browsers like Opera are locked out of important preinstallation opportunities, and then Microsoft frustrates users' ability to download and use alternative browsers," McParlan stated.

Opera's complaint is particularly relevant in the context of Brazil, where it claims to be the third-most popular PC browser, capturing 6.78% of the desktop market share as of June 2025, according to StatCounter. In contrast, Microsoft Edge holds 11.52%, while Google's Chrome dominates with a staggering 75%. Opera asserts that Microsoft's tactics include incentivizing major PC manufacturers to pre-install Edge exclusively, further limiting the visibility of competing browsers.

This complaint follows Opera's previous legal action against the European Commission, which it accused of exempting Microsoft Edge from the Digital Markets Act—legislation aimed at curtailing the power of large technology firms. Experts in antitrust law have noted that Opera's latest complaint aligns with a broader global scrutiny of Big Tech practices, especially in light of recent regulatory frameworks designed to promote fair competition.

Dr. Emily Carter, a professor of law at Stanford University and an expert in antitrust regulations, commented, "This case not only illustrates the ongoing battle between smaller tech companies and established giants but also reflects a growing trend among regulators worldwide to investigate anti-competitive practices more rigorously."

Microsoft has yet to respond publicly to the allegations. However, the implications of this case could be significant, not only for the competitive landscape in Brazil but also for how antitrust authorities globally approach similar complaints. As the digital marketplace continues to evolve, the outcome of this investigation may serve as a crucial precedent for future regulatory actions involving technology companies.

In conclusion, as the rivalry between Opera and Microsoft intensifies, industry observers will be closely monitoring CADE's response and any potential changes in the competitive dynamics of the web browser market. Should CADE find merit in Opera's complaint, it may lead to substantial changes in how Microsoft operates in Brazil and possibly influence regulatory approaches in other regions as well.