March 20 (Reuters) - Super Micro shares sank 27% on Friday after U.S. prosecutors charged three people linked with the company, including its co-founder, with helping smuggle billions of dollars worth of AI technology to China.

The drop in premarket trading would erase nearly $5 billion from Super Micro's $18.49 billion market value if the losses hold.

U.S. prosecutors did not name Super Micro - a major AI server builder using Nvidia's chips - in the complaint. The company confirmed it was not named as a defendant in the case, and that it had cooperated with investigators.

The Department of Justice has charged its co-founder Yih-Shyan Liaw, Taiwan-office sales manager Ruei-Tsang Chang and contractor Ting-Wei Sun on allegations of a complex scheme to send U.S.-made servers via Taiwan to other countries in Southeast Asia. From there, they were swapped into unmarked boxes and sent onward to China.     

The accused were charged with helping smuggle at least $2.5 billion of U.S. AI technology to China, with products worth more than half a billion dollars sent between April and mid-May 2025, the Justice Department said. 

Super Micro has placed the employees on leave and ended its relationship with the contractor.

The U.S. imposed chip export controls in 2022 to make sure Beijing's military would not benefit from its technology, and to slow the development of China's AI efforts.

San Jose, California-based Super Micro earlier said that the restrictions impacted certain products, including those that contain the Nvidia A100 and H100 integrated circuits, among others.

Soaring demand for AI chips had sent Super Micro's valuation to a peak of $67 billion in 2024, but margin pressure from building the costly servers and allegations from the now-disbanded short-seller Hindenburg have since dragged the stock lower.