If a judge orders Google to sell Chrome, it could dramatically upend the multibillion-dollar online search business.

The US government formally proposed a partial breakup of Google on Wednesday, urging a federal judge to force a sale of the company’s Chrome web browser after a landmark ruling this year finding that Google had violated US antitrust law with its search business.

The United States Department of Justice argued Wednesday that Google should divest its Chrome browser as part of a remedy to break up the company's illegal monopoly in online search, according to a U.