Several cryptocurrency traders are planning on filing a lawsuit against cryptocurrency exchange Coincheck for freezing withdrawals after the company suffered a security breach earlier this year.

Ten people plan to take part in the lawsuit, which is set to be filed at the Tokyo District Court in Japan on Feb. 15. The lawyer representing the 10 claimants announced the planned lawsuit to Reuters on Tuesday.

At issue in the lawsuit is Coincheck, a Tokyo-based cryptocurrency exchange, and its decision to freeze all withdrawals after it fell victim of a security breach that resulted in more than $530 million of NEM tokens being stolen from traders.

Prior to confirming the breach, Coincheck halted operations, including preventing traders from withdrawing their money from the exchange—a decision that left that money in limbo while the cryptocurrency markets continued to move.

Coincheck Cryptocurrency traders planning to sue Coincheck over hack. Photo: Cryptocoinjapan/Wikimedia Commons

The plaintiffs in the upcoming lawsuit intend to ask Coincheck to allow traders to withdraw their cryptocurrency from the exchange and transfer it to a digital wallet. A second lawsuit will also seek reparations for damages caused to the investors by the hack.

Coincheck has also struggled to return to full operation since the hack, but did announce Monday that it would allow users to begin withdrawing their cryptocurrency in yen. More than $370 million was immediately withdrawn from the exchange.

With the lawsuit looming, Coincheck also faces a deadline Tuesday to submit a report on the hack, including an outline on how the company will change its security protocols to prevent future breaches, to Japan’s Financial Services Agency (FSA). The agency also conducted an inspection of Coincheck on Feb. 2.

Japan has been an early adopter of cryptocurrency, going so far as to recognize the cryptocurrency as a legal payment method in 2017. The country has also been on the forefront of regulating cryptocurrency markets and began issuing licenses to exchanges operating within the country.

Coincheck has taken some steps to rehabilitate its image in the wake of the hack. It announced a plan to provide reparations to the users affected by the breach, including nearly 260,000 people who had cryptocurrency stolen from them.

In terms of sheer volume, the Coincheck breach represented the largest hack in the history of cryptocurrency, topping even the infamous Mt. Gox incident that resulted in 850,000 Bitcoins—then valued at about $450 million—being stolen.

Details on the cause of the breach are still mostly unknown, though intelligence officials in South Korea have reportedly suggested that North Korean hackers may have been responsible for the massive theft of cryptocurrency from Coincheck.