Shares of chip company Advanced Micro Devices and server maker Super Micro Computer tumbled in premarket trading on Wednesday after the companies posted underwhelming results in their data center segments, shaking investor confidence in their AI growth narratives. AMD dropped nearly 5%, while Super Micro plummeted about 17%. The selloff comes as chipmakers face mounting headwinds, including weak demand, rising inventories, and the threat of new U.S. tariffs on semiconductor imports, expected as early as next week.