BitMEX, the crypto derivatives exchange credited with inventing the perpetual swap, is facing a proposed class-action lawsuit alleging theft of bitcoin and insider trading — filed on the same day the exchange announced it would cease operations within three months.

The complaint was filed on July 23 in the U.S. District Court for the Southern District of New York by BKX Services, a former tokenization project, and David Namdar. The plaintiffs allege that BitMEX designed a system intended to retain customer collateral and transfer remaining bitcoin to the platform's insurance fund. They further claim that an internal trading desk had access to private customer information and could continue trading during server freezes that prevented other users from closing their positions.

BKX Services claims it lost at least 305.81 BTC through forced liquidations, while Namdar alleges losses exceeding 316.85 BTC. Combined, the plaintiffs cite 622.66 BTC — approximately $40.7 million — as the amount allegedly owed to them. BitMEX allowed traders to borrow up to 100 times their collateral to leverage positions, and the plaintiffs allege the platform liquidated their positions while the collateral was still worth roughly twice the losses, withholding the balance.

The lawsuit names parent company HDR Global Trading, several affiliates, and co-founders Arthur Hayes, Ben Delo, and Samuel Reed as respondents. Hayes, Delo, and Reed previously pleaded guilty in 2022 to violating the Bank Secrecy Act by willfully failing to establish an adequate anti-money-laundering program at BitMEX, as part of a settlement with U.S. regulators that also included a $100 million civil penalty from the CFTC and FinCEN. The plaintiffs seek to represent all U.S. customers who purchased BitMEX bitcoin swap products dating back to July 23, 2018. They are seeking the return of the bitcoin, along with compensatory and punitive damages. The case requires a judge's approval to proceed as a class action. The court docket is available via CourtListener.

Similar claims were raised in a 2020 class-action case, which was closed in June 2025 without a ruling on the liquidation allegations.

The filing coincided with BitMEX's announcement that it would close on September 23, bringing an end to its 11-year run as a crypto derivatives exchange. At its peak in 2018, BitMEX regularly processed billions of dollars in daily trading volume and was the dominant venue for crypto leveraged trading, but its market share eroded significantly as competitors like Binance, Bybit, and OKX expanded their derivatives offerings with similar products and deeper liquidity. The closure followed a strategic review by HDR and a broader management shake-up. Last month, BitMEX lost its CEO, chief financial officer, and head of growth, with general counsel Peter Wilkinson stepping in as the new CEO.

The timing of the lawsuit against a winding-down exchange raises practical questions about asset recovery for affected users, as class certification and litigation timelines may extend beyond BitMEX's planned September closure date.

CoinDesk reached out to BitMEX and the other defendants for comment but had not received a response by publication time.

Source: CoinDesk