A GameStop Corp. store in Rome, Italy, on Thursday, Jan. 28, 2021. GameStop Corp. had the biggest day yet of its dizzying rally, adding more than $10 billion in market value, as bullish day traders kept the upper hand over short sellers. Photographer: Alessia Pierdomenico/Bloomberg 
Brokerages are implementing curbs after the stocks swung wildly on orders from retail investors inspired by WallStreetBets and other online forums. GameStop soared more than 400% in the first three days of this week, attracting interest from traders around the world. It tumbled 44% on Thursday after brokerages began announcing restrictions, triggering a flood of angry responses from customers.
Extreme volatility in the stocks has “generated substantial risk” for brokerages, resulting in the need for stricter requirements on those firms, the Depositary Trust & Clearing Corp., a Wall Street clearinghouse, said on Thursday.
Some overseas brokerages have continued to allow trading in GameStop. South Korea’s major brokerages -- Korea Investment & Securities Co., NH Investment & Securities Co., Mirae Asset Daewoo Co. -- said on Friday they don’t have plans to impose restrictions.
Webull, another retail trading platform in the U.S. founded by Alibaba Group Holding Ltd. alum Wang Anquan, also said opening and closing positions in GameStop and AMC Entertainment Holdings are unaffected.