(Bloomberg) -- Taiwan’s MediaTek Inc. led a slump among major chipmakers after the Trump administration tightened restrictions on Huawei Technologies Co., expanding a campaign to cripple China’s largest tech corporation.The rules announced Monday build on restrictions announced in May and add 38 Huawei affiliates in 21 countries to an economic blacklist. All chip companies working for Huawei will be subject to licensing regardless of where they are, an official said, adding that even foreign companies will be affected as long as they use American design software or equipment.MediaTek sank as much as 9.9%, paring its 54% surge this year, after the stock was downgraded to neutral by Credit Suisse. The company stressed Tuesday it was monitoring the latest sanctions but the curbs had no material impact on its operations.Novatek Microelectronics Corp. and Realtek Semiconductor Corp., whose chip designs are used by Huawei, dropped more than 6% in Taipei. In Hong Kong, smartphone suppliers Sunny Optical Technology Group, AAC Technologies Holdings Inc. and BYD Electronic International Co. fell.The Commerce Department in May banned the sale of any silicon to Huawei made with U.S. know-how -- striking at the heart of its semiconductor apparatus and aspirations in fields from artificial intelligence to mobile services. Its stockpiles of certain self-designed chips essential to telecom equipment will run out by early 2021, according to people familiar with the matter.The earlier restrictions required companies manufacturing chips designed by Huawei’s HiSilicon unit to obtain licenses, fueling expectations that third-party designers like MediaTek would win orders from the Chinese giant. Commerce Secretary Wilbur Ross said the latest restriction was aimed at closing loopholes the company explored after previous U.S. actions.Read more: U.S. Announces New Curbs on Huawei Access to U.S. Technology“The U.S. closing the loophole on its direct product rule is a surprise, but not totally unexpected,” Jefferies analysts including Edison Lee wrote in a note. “That means the hope Huawei could rely on third-party chip designers such as MediaTek and Unisoc to continue making handsets has been dashed. It also puts Huawei’s survival at risk.”Escalating Washington-Beijing tensions have increasingly ensnared Chinese technology champions from ByteDance Ltd. to WeChat-operator Tencent Holdings Ltd., though Huawei remains the company most under siege from the White House.The Trump administration’s latest blow follows earlier steps including a ban on supplying American technology to Huawei, convincing allies like the U.K. to bar the firm’s networking gear, and the arrest of its founder’s daughter in Canada.Read more: Huawei Sees Dire Threat to Future From Latest Trump Salvo“Investors should consider possible second-order effects,” Bernstein analysts including Mark Li wrote. “The reality may not be as bad as the ‘bear case’ as some approvals may be granted. But whether China will retaliate, and the future preference of Chinese original equipment manufacturers between U.S. and non-U.S. suppliers, are also risks.”(Updates with share action and Mediatek’s statement from the third paragraph)For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.