Japanese cryptocurrency exchange DMM Bitcoin said Friday it had lost 4,502.9 bitcoin, worth about ¥48.2 billion ($308 million), in what the company called an “unauthorized leak.”
It did not provide details on how the incident occurred or whether a third party was involved, but said it was investigating and had restricted some services in response.
Cryptocurrency companies are often the target of hacks and cyber attacks, although losses of this magnitude are rare.
DMM Bitcoin said it would replace customers’ lost Bitcoin deposits with the help of other group companies.
The Financial Services Agency demanded that the company investigate the incident, public broadcaster NHK said.
Tom Robinson, chief scientist and co-founder of crypto research firm Elliptic, said that if the DMM loss turned out to be theft, it would be the eighth largest crypto theft of all time, based on exchange rates at the time it occurred.
It would be the largest since the $477 million hack that FTX suffered in November 2022, he added.
Crypto news outlet CoinDesk said the DMM loss was the second largest the region had suffered, after $530 million worth of cryptocurrency was stolen from Japanese crypto exchange Coincheck in 2018.
About $1.7 billion was stolen from various cryptocurrency platforms last year, according to crypto research firm Chainalysis.
