China finds Nvidia broke antitrust law and extends probe. Shares are dropping.

Nvidia shares were under pressure ahead of Monday’s stock market open after China’s top regulatory authority said the U.S. chipmaker has violated the country’s antitrust rules.

The State Administration for Market Regulation said in a brief statement that following a preliminary investigation, Nvidia was found to be in breach of those rules, with relation to its acquisition of Mellanox Technology Co., Ltd. with Restrictive Conditions.