Google has been hit with a third antitrust fine from European Union regulators over alleged antitrust violations related to ad sales, as calls to break up big tech grow.

European Commissioner for Competition Margrethe Vestager tweeted Wednesday that the EU fined Google 1.49 billion euros ($1.69 billion) for “illegal practices in search advertising brokering.” She claimed the Mountain View, California-based company misused its dominant position in search ads—holding more than 70 percent of the EU market from 2006 to 2016—by imposing “contractual restrictions on third-party sites.”

The fine stems from Google's “AdSense for Search” program, which brokered ad deals between website publishers offering in-site search functions and advertisers. According to the European Commission, Google contractually prohibited competitors' advertisements from appearing in third-party websites' search results starting in 2006.

“This is illegal under EU antitrust rules,” Vestager said in a press release. “The misconduct lasted over 10 years and denied other companies the possibility to compete on the merits and to innovate—and consumers the benefits of competition.”

The commission said Google began shifting to a “premium placement” model in 2009. It required publishers, such as news sites, to place Google's advertisements in the most profitable part of their website's search results, over competitors. The same year, Google also allegedly included clauses mandating publishers get the company's approval before changing rivals' advertisements, allowing it to “control how attractive, and therefore clicked on, competing search adverts could be.”

Google stopped the practices in July 2016 after the commission issued a statement of objections. But the latest fine, accounting for 1.29 percent of Google's 2018 global turnover, is meant to prevent the company from implementing similar practices.

“We've always agreed that healthy, thriving markets are in everyone's interest. We've already made a wide range of changes to our products to address the Commission's concerns,” said Kent Walker, Google's senior vice president for global affairs and legal department head, in a statement Wednesday. “Over the next few months, we'll be making further updates to give more visibility to rivals in Europe.”

Wednesday's fine is the third in a series of European Commission antitrust penalties against Google. In July, EU regulators fined Google a massive 4.34 billion euros ($5 billion), claiming Google-owned Android phones pushed users toward the company's search engine over competitors. Google was hit with a fine of 2.42 billion euros ($2.72 billion) from the commission in 2017 for promoting its own shopping comparison site over others on its search engine.

Google's EU antitrust fines now total more than $9 billion.

Walker said Google has “been listening carefully to the feedback we're getting” from the commission, in a blog post Tuesday. The company has changed its licensing mode for Google apps since the 2018 fine, making it easier for Android phone users to install competing browsers and search functions, he noted. Since 2017, Google has adapted its shopping feature to better promote competition.

Backlash over Google's size and practices more recently came stateside. Earlier this month, presidential candidate Sen. Elizabeth Warren, D-Massachusetts, called for a breakup of tech companies, including Google, promising to retroactively split mergers and acquisitions if elected.

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