A British software engineer, Lewis Barber, is suing BitMEX operator HDR Global Trading in London for the return of 324.8 bitcoin, worth roughly $27.2 million. The software engineer alleges that the shuttered exchange sold him derivatives in the UK without approval from the Financial Conduct Authority (FCA).Why is BitMEX getting sued?A British software engineer called Lewis Barber placed about 2,294 trades on BitMEX across five accounts between 2018 and 2022, the Guardian reported, citing the particulars of claim. Barber sued BitMEX over the 1,053 of his trades that lost money. Each one was a perpetual swap, a derivative that works like a futures contract but never expires.In December 2025, Barber’s solicitors wrote to BitMEX to rescind his trades based on the Financial Services and Markets Act 2000. Under that law, every swap he traded was a regulated activity, and BitMEX held no UK authorization to offer them. He says this makes the contracts unenforceable against him and entitles him to be repaid what he lost. He also alleges BitMEX knew it wasn’t authorized but still implied that trading with him was lawful.The bitcoin Barber wants back was valued at £20.4 million on October 1, but the number reportedly shoots up to about $27.2 million when calculated using the exchange rates in the filing. The claim has been filed at the High Court but not served. It points out BitMEX’s marketing reach, saying the exchange ran promotional campaigns worldwide, let users register the UK as their country of residence, and placed an advertisement in The Times on January 3, 2019.The claim mentions a public warning the UK’s Financial Conduct Authority (FCA) issued on March 3, 2020, which told UK consumers that BitMEX wasn’t authorized by the FCA. Due to that, anyone trading on it would have no access to the Financial Ombudsman Service or the Financial Services Compensation Scheme. Is BitMEX in other legal trouble?Cryptopolitan reported that BitMEX stopped trading on September 23, 2026, after more than 11 years in operation. HDR Global, the Seychelles company that runs it, said it decided to shut down after failing to find a buyer in 2025. Verified users who still have money on the platform will now be charged a fee of $50 per month or 1% per year, whichever is higher.Apart from the claim in London, BitMEX is accused of running a hidden “Insider Trading Desk” in New York that traded against customers and froze its servers during volatile periods to force liquidations. BKX Services and David Namdar filed the proposed class action in July. The plaintiffs say they lost about 623 bitcoin between them and want the coins returned. BitMEX has denied the allegations.BitMEX’s co-founder Ben Delo has drawn separate attention in Britain for donating £36 million to Reform UK. Notably, Delo, Arthur Hayes, and Samuel Reed pleaded guilty in 2022 to breaking U.S. anti-money laundering law (the Bank Secrecy Act). They avoided prison, and President Trump pardoned them in March 2025. BitMEX pleaded guilty to the same offense in 2024 and paid the U.S. Department of Justice $100 million in January 2025.The UK suit is similar to a June 2026 case in which nearly 1,700 investors sued Binance and Changpeng Zhao over unauthorized derivatives sales, a case that targets more than £150 million.The smartest crypto minds already read our newsletter. Want in? Join them.