Japanese crypto exchange reports bitcoin theft worth $305M

DMM Bitcoin said customer bitcoin deposits “will be fully guaranteed” in the wake of the hack


Artwork by Crystal Le


A Japanese crypto exchange operator said Friday that it suffered an “unauthorized leak” of more than $300 million worth of bitcoin.

The details were shared in a blog post published by DMM Bitcoin. The total amount said to be stolen was 4,502.9 BTC, worth $305.1 million at current market prices.

The exchange said that customer bitcoin deposits “will be fully guaranteed as we will procure the equivalent amount of BTC that was leaked with support from our group companies.” DMM Bitcoin offered no timeline on when these procurements would take place.

DMM Bitcoin said the theft occurred at 1:26 p.m. Tokyo time. That time roughly aligns with the timing of a transaction worth 4,502 BTC flagged by the Whale Alert account on X, formerly Twitter. 

DMM Bitcoin said that it has stopped processing crypto withdrawals and spot market purchase orders, as well as new leveraged trading positions. The exchange is also “screening” new account openings.

Withdrawals denominated in yen, the exchange said, “may take longer than usual,” per the blog post.

The exchange didn’t say when services would resume, but that a separate announcement would be published with more information. 

According to a report from Japanese news service Nikkei, DMM Bitcoin had approximately 370,000 customer accounts at the end of 2023, citing an annual business report. 

If confirmed, the amount stolen represents one of the largest-ever crypto exchange attacks.

In 2018, Coincheck suffered a theft worth 58 billion yen, or about $533 million worth of crypto. The exchange was acquired by online brokerage firm Monax later that year.

Japan was home to arguably the most infamous of bitcoin exchange collapses, Mt Gox, with losses valued at more than $400 million in 2014 prices. The failure of Mt Gox kicked off a decade-long process that appears nearing completion, with preparations underway to finally distribute funds to creditors.

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