PubMatic, a major player in the digital advertising ecosystem, has filed a lawsuit against Google in federal court, accusing the tech giant of illegally monopolizing the ad technology market. The case, filed on September 9, 2025, comes at a time when regulators and industry rivals are stepping up scrutiny of Google’s dominance in online advertising.

According to PubMatic, Google has engaged in anti-competitive practices that restrict fair competition within the digital ad exchange and ad server markets. The company argues that Google’s tightly controlled ecosystem forces advertisers and publishers into using its own platforms and services, effectively sidelining competitors. This claim builds on a previous ruling where a federal judge found that Google had unlawfully dominated ad exchanges and ad servers, reinforcing allegations that its practices harm both advertisers and publishers.

The lawsuit reflects broader industry frustration with Google’s entrenched market power. Digital advertising remains the backbone of the internet economy, yet critics argue that Google’s control of the pipeline — from ad buying to placement and analytics — leaves little room for independent companies to thrive. PubMatic contends that Google’s behavior has resulted in higher costs, limited transparency, and fewer choices for both advertisers and content creators.

Google, which is already facing multiple antitrust investigations across the U.S. and Europe, is expected to challenge PubMatic’s claims. The company has previously defended its practices by asserting that its ad products drive efficiency, reduce fraud, and create value for publishers and marketers.

This legal battle could carry significant implications for the digital advertising sector. If successful, PubMatic’s lawsuit may pave the way for structural changes in how online ads are bought and sold, potentially creating more open competition in a market long dominated by Google.