Google lost its biggest regulatory battle yet, getting a record 2.4 billion-euro ($2.7 billion) fine from European Union enforcers who say the search-engine giant skewed results to thwart smaller shopping search services.

Alphabet Inc.'s Google has 90 days to "stop its illegal conduct" and give equal treatment to rival price-comparison services, according to a binding order from the European Commission on Tuesday. It's up to Google to choose how it does this and inform the EU of its plans within 60 days. Failure to comply brings a risk of fines of up to 5% of its daily revenue.

"The more consumers click on comparison shopping results, the more money Google makes," said Margrethe Vestager, the EU's antitrust chief. "This decision requires Google to change the way it operates and to face the consequence of its actions."