Last year, the EU competition enforcer imposed a record €4.34 billion fine on Google for using its popular Android mobile operating system to block rivals.

European Union (EU) antitrust regulators handed down a €1.49 billion fine to Google on Wednesday for blocking rival online search advertisers, marking the company’s third penalty in two years.

EU’s competition commissioner Margrethe Vestager announced the results of the long-running probe of Google’s AdSense advertising business at a news conference in Brussels on Wednesday.

“Today’s decision is about how Google abused its dominance to stop websites using brokers other than the AdSense platform,” Ms. Vestager said.

The commission found that Google and its parent company, Alphabet, breached the EU antitrust rules by imposing restrictive clauses in contracts with websites that used AdSense, preventing Google rivals from placing their ads on these sites.

Google “prevented its rivals from having a chance to innovate and to compete in the market on their merits,” Ms. Vestager said. “Advertisers and website owners, they had less choice and likely faced higher prices that would be passed on to consumers.”

AdSense is an older Google product that lets web publishers such as bloggers place text ads on their websites, with the content of the ads based on results from search functions on their sites.

Microsoft's complaint

Microsoft filed an EU antitrust complaint about the service in 2009 and the EU Commission formally launched its probe in 2016, although it said at the time that Google had made some changes to allow affected customers more freedom to show competing ads.

Last year, the EU competition enforcer imposed a record €4.34 billion fine on Google for using its popular Android mobile operating system to block rivals. This followed a €2.42 billion fine in 2017 for hindering rivals of shopping comparison websites.