UK Trader Sues BitMEX for $27 Million in Bitcoin, Alleging Unauthorized Derivatives Trading

A British software engineer has filed a High Court claim seeking the return of 324.8 bitcoin — valued at approximately $27.2 million at current prices — from the operators of the shuttered crypto derivatives exchange BitMEX, arguing that every trade he placed on the platform was unenforceable under U.K. law because the exchange lacked authorization from the Financial Conduct Authority.

Lewis Barber, who traded through five accounts between 2018 and 2022, executed roughly 2,294 perpetual swap contracts on BitMEX, according to court documents reviewed by The Guardian and Decrypt. He is challenging the 1,053 trades that resulted in losses, contending that each transaction constituted a regulated activity under the Financial Services and Markets Act 2000 (FSMA). Because HDR Global Trading Limited, the Seychelles-registered entity behind BitMEX, never held FCA permission to carry on that activity in the United Kingdom, Barber’s legal team asserts the contracts are void and unenforceable under Sections 26 and 29 of FSMA.

Perpetual swaps, the flagship product offered by BitMEX, function similarly to futures contracts but have no expiration date, allowing traders to hold leveraged positions indefinitely so long as they maintain margin. In the U.K., offering such derivatives to retail clients falls squarely within the FCA’s regulatory perimeter, and the regulator has repeatedly warned that firms selling crypto-derivatives to U.K. consumers must be authorized.

The claim alleges BitMEX actively courted U.K. customers: the platform did not block access from British IP addresses, allowed new users to select “United Kingdom” as their country of residence during onboarding, and ran a promotional advertisement in The Times in January 2019. The FCA itself issued a public warning in March 2020 stating that BitMEX “may have been” providing regulated products in the U.K. without permission.

Beyond restitution of the bitcoin, Barber is pursuing damages for deceit, arguing that BitMEX implicitly represented it was lawfully authorized to trade with him while knowing it was not. His solicitors, Seladore Legal, sent a formal notice of rescission in December 2023 — a procedural step intended to unwind the contracts ab initio.

The case has been filed in the Commercial Court but has not yet been formally served on HDR Global Trading. A BitMEX spokesperson told The Guardian the company had not received any claim.

Seladore partner Gareth Keillor said the firm believes “many other U.K.-based persons” may have entered into similar contracts, and that aggregate exposure could reach “hundreds of millions of pounds.” Whether any individual has a viable claim will depend on specific trading history and residency status at the time of each transaction.

The lawsuit arrives against a backdrop of mounting legal pressure on BitMEX and its founders. In the United States, a proposed class action in the Southern District of New York accuses the exchange and its three co-founders — Ben Delo, Arthur Hayes, and Samuel Reed — of bitcoin misappropriation and insider trading. All three pleaded guilty in 2022 to violating the Bank Secrecy Act through anti-money-laundering failures; they were pardoned by President Donald Trump in March 2025. BitMEX itself pleaded guilty to BSA violations in 2024 and was ordered to pay a $100 million penalty in January 2025.

The exchange ceased operations on September 23, 2024, after announcing its wind-down in July. Shortly before the shutdown, Delo donated £36 million to the Reform UK party, the largest single political donation in British history.

Barber’s claim represents the first known U.K. court test of whether offshore crypto derivatives platforms can be held liable for trading with British residents without FCA authorization — a question that could reshape how regulators and courts treat cross-border digital-asset activity.