Bithumb Accidentally Gave Away $43 Billion in Bitcoin and Now the Courts Want It Back

South Korean crypto exchange Bithumb has scored another legal victory in its effort to recover money from users who sold Bitcoin they received during one of the biggest “fat-finger” errors in crypto history. A Seoul court ordered a customer to return roughly 194 million won, or about $140,000, after the user sold BTC that Bithumb accidentally credited to their account.

The ruling is Bithumb’s second win out of four civil lawsuits connected to the February incident, strengthening the exchange’s argument that customers can’t legally keep profits generated from an obvious accounting mistake. 

One Wrong Click Created 620,000 Bitcoin

The incident began on February 6 during a Bithumb promotional giveaway.

A staff member reportedly entered BTC instead of KRW as the reward unit, causing the exchange’s internal system to credit users with an astonishing 620,000 BTC — worth roughly $43 billion at the time. 

For perspective, the 620,000 BTC wasn’t actually transferred across the Bitcoin blockchain. The balances existed primarily inside Bithumb’s internal ledger, and the exchange reportedly held only around 46,000 real BTC at the time. 

Some customers quickly realized what happened and started selling the accidental Bitcoin before Bithumb could stop them.

That triggered chaos.

• Bithumb’s BTC-KRW price briefly plunged roughly 15%
• The exchange froze affected accounts and recovered most of the erroneous balances
• Approximately 1,788 BTC had already been sold before the freeze
• Bithumb ultimately recovered about 99.7% of the mistaken credits

Bithumb Takes Four Customers to Court

Most users voluntarily returned the accidental funds, but several refused.

Bithumb responded by filing four unjust enrichment lawsuits in March against customers who sold the mistakenly credited Bitcoin and retained the proceeds. 

The four claims are worth approximately:

500 million won ($362,000), 194 million won ($140,000), 14.8 million won ($10,700) and 5 million won ($3,600).

Bithumb has now won the 194 million won and 5 million won cases, leaving two lawsuits unresolved. 

The latest ruling came from the Seoul Central District Court, which ordered the defendant to return the proceeds obtained from selling the erroneous Bitcoin. 

Users Argued the Mistake Was Bithumb’s Problem

The legal dispute raises an interesting question for centralized crypto exchanges.

If an exchange accidentally puts cryptocy into your account, and you manage to sell it before the company reverses the transaction, is the money yours?

Some recipients reportedly argued they weren’t obligated to return the funds because Bithumb caused the mistake, not them. 

The court’s rulings so far are siding with Bithumb.

The exchange is pursuing the cases under the principle of unjust enrichment, essentially arguing that customers shouldn’t financially benefit from assets they knew — or reasonably should have known — were credited by mistake.

With two victories already secured, the rulings could strengthen Bithumb’s position in the remaining cases.

The $43 Billion Mistake Exposed a Bigger Problem

The incident also attracted scrutiny from South Korean regulators because Bithumb’s internal system was capable of creating customer balances representing vastly more Bitcoin than the exchange actually possessed.

Bithumb CEO Lee Jae-won acknowledged during a parliamentary hearing that the company’s internal controls failed to detect that more crypto had been credited than was actually available. 

The Financial Services Commission has since discussed tighter safeguards, including more frequent reconciliation between exchange ledgers and actual cryptocy holdings. 

Bithumb also pledged to compensate customers affected by the temporary Bitcoin price collapse and strengthen its internal controls. 

The exchange is now targeting 2028 for its planned IPO, after the incident contributed to additional regulatory scrutiny surrounding its operations. 

Bithumb’s Biggest Mistake Is Becoming a Legal Test Case

Bithumb managed to recover almost all of the 620,000 BTC credited during the error, but the remaining disputes could have consequences beyond one exchange.

Centralized crypto platforms rely heavily on internal databases rather than settling every customer trade directly onchain. That makes safeguards preventing exchanges from creating unbacked balances especially important.

Bithumb’s mistake demonstrated what can happen when those controls fail.

Now South Korean courts are answering the next question: What happens when customers spend the money before the exchange realizes its mistake?

So far, the answer isn’t looking good for the customers.

Bithumb made the $43 billion mistake, but the courts are saying users can’t keep the profits.