Elizabeth Warren, the ranking member of the U.S. Senate Committee on Banking, Housing and Urban Affairs, sent a letter to the Commerce Department’s under secretary for industry and security invoking the Export Control Reform Act of 2018 to require documents and information on alleged loopholes in U.S. export controls for advanced semiconductors. The letter centers on Warren’s claim that the Bureau of Industry and Security’s rescission and non-enforcement of the Biden administration’s AI Diffusion Rule weakened controls meant to prevent diversion of advanced AI chips to China, including by firms such as Huawei. Warren focused on what she described as an open loophole tied to the Foundry Due Diligence Rule, which BIS implemented in January 2025 after Huawei used an intermediary shell entity to order potentially millions of advanced chips from Taiwan Semiconductor Manufacturing Company. That rule requires foundries to presume certain advanced chip exports need a license unless specified due diligence is completed. Warren argued the rule depended on the AI Diffusion Rule’s worldwide licensing requirement, and that BIS’s rescission and failure to issue the promised replacement more than a year later removed the license trigger that made the foundry controls effective. Citing ECRA, Warren said the department must provide information obtained under the Export Administration Regulations upon request from the committee chair or ranking member. She asked BIS to provide the requested materials by Aug. 6, 2026.