The US government opposes sharing with Google other companies’ sensitive information in an antitrust lawsuit because it says that would undermine trust and hamper future investigations.

The US Justice Department sued Alphabet Inc’s Google last month accusing it of abusing its monopoly in its search engine, the most significant antitrust action against an American company in more than two decades - and possibly a century.

Google is seeking access to confidential information the United States has obtained from third parties to prepare for trial. It’s proposing that the sharing of information be done only with its in-house counsel. It also wants advance notice if the information is used in other matters, according to a Justice Department filing in Washington federal court on Nov 13.

"Adopting Google’s proposal would undermine third parties’ confidence in the treatment of their confidential information, chill third-party cooperation in current and future government investigations, and unfairly advantage Google in the marketplace if third-party confidential information is disclosed or used,” the United States said in the filing.

The judge in the case has given companies including Microsoft Corp, Oracle Corp, Amazon.com Inc, AT&T Inc and Comcast Corp until Nov 20 to stake out a position on restricting their information that may be shared by the government with Google during the litigation. The companies called it a "serious concern” in a joint filing, saying they have produced some of their "most sensitive internal business materials”.

Google controls about 90% of the online search market in the United States and generates most of the company’s revenue. It has funded its expansion into email, online video, smartphone software, maps, cloud computing, autonomous vehicles and display advertising.

The case is US v Google, 20-cv-03010, US District Court, District of Columbia (Washington).

 - Bloomberg