By Karen Freifeld

July 2 (Reuters) - Alpha and Omega Semiconductor Limited AOSL.O has agreed to pay $4.25 million to settle with the U.S. Department of Commerce for shipping items to China's Huawei Technologies in violation of export regulations, according to a department order posted on Wednesday.

AOS engaged in prohibited conduct by forwarding 1,650 power controllers, smart power stages and related accessories to Huawei without authorization in 2019, the year Huawei was added to a restricted U.S. trade list, the order said.

Though the items were foreign designed and produced, the order said, they were subject to export control regulations because AOS exported them from the United States. Suppliers to companies on the restricted trade list, known as the Entity List, are required to obtain licenses.

U.S. authorities have been investigating AOS' transactions since 2019, the company said in an SEC filing earlier this year. In January 2024 the Justice Department closed its investigation without charges, the filing said, but a civil investigation by the Commerce Department was ongoing.

On April 16, 2025, AOS said it received a letter from Commerce alleging violations of export control regulations, and the company met to discuss a possible resolution.

AOS, which is headquartered in Sunnyvale, California, operates in both the United States and Asia. It has a wafer fabrication facility in Hillsboro, Oregon.

In 2020, the United States added to Huawei's Entity listing to expand its authority to stop shipments of foreign-produced items to Huawei.

AOS did not immediately respond to a request for comment.

(Reporting by Karen Freifeld; Editing by Mark Porter)

((karen.freifeld@thomsonreuters.com; +1(646) 223-6921;))