By Jonathan Stempel
March 25 (Reuters) - Shareholders of Super Micro Computer sued the Silicon Valley server maker on Wednesday, accusing it of committing securities fraud by concealing its dependence on sales to China that violated U.S. export laws, leading to criminal smuggling charges involving Nvidia chips against a co-founder and two others linked to the company.
In a proposed class action filed in San Francisco federal court, shareholders said Super Micro overstated its business prospects and
inflated its stock price by knowingly failing to disclose that a significant portion of server sales went to companies in China, and the company had material weaknesses in its compliance with export control laws.
Super Micro shares sank 33% on March 20 after criminal charges were announced a day earlier against Yih-Shyan Liaw, a co-founder and director; Ruei-Tsang Chang, a sales manager in Taiwan; and Ting-Wei Sun, a contractor.
The decline wiped out about $6.1 billion of the San Jose, California-based company's market value, and Liaw resigned from Super Micro's board.
Other defendants in the civil lawsuit are Chief Executive Charles Liang and Chief Financial Officer David Weigand. Super Micro did not immediately respond to requests for comment.
Prosecutors in the criminal case said Liaw and Chang directed an unnamed company in Southeast Asia to buy servers with Nvidia's chips, and that the company bought $2.5 billion of servers in 2024 and 2025.
Super Micro has said it is cooperating with the government, and the alleged criminal conduct violates its policies. Neither Super Micro nor Nvidia was criminally charged, and Nvidia is not a defendant in the shareholder lawsuit.
It is common for shareholders to sue companies after unexpected negative news causes stock prices to decline.
Wednesday's lawsuit seeks unspecified damages for Super Micro investors between April 30, 2024, and March 19, 2026.
(Reporting by Jonathan Stempel in New York; Editing by Matthew Lewis)
