The fallout from a large-scale bitcoin mispayment incident at Bithumb is spreading. Despite the company's emergency recovery measures, some assets were leaked outside, prompting financial authorities and the National Assembly to signal tighter related regulations.

Financial authorities and the industry said on Feb. 9 that 125 BTC, worth about 13 billion won, has yet to be recovered from the bitcoin paid out due to a computer error at Bithumb on Feb. 6.

The incident occurred around 7 p.m. on Feb. 6 during the payout process for rewards in a "random box" event. A Bithumb employee mistakenly entered the reward unit as bitcoin, not won, resulting in winners receiving 2,000 BTC each instead of 2,000 won.

As a result, a total of 620,000 BTC was issued on the system and deposited into users' accounts. Based on the price at the time of the incident, about 98 million won, it was worth about 60.76 trillion won. That is about 15 times more than the roughly 42,000 bitcoins Bithumb actually holds.

Bithumb blocked deposits and withdrawals about 35 minutes after the incident and began recovering the assets, but failed to recover all of them as some users sold or withdrew the assets.

Financial authorities found that 86 users sold the mispaid bitcoin. Some of them withdrew about 3 billion won in proceeds to commercial bank accounts and took the funds outside Bithumb. The remaining amount, estimated at about 10 billion won, is believed to have been exchanged into other digital assets such as ethereum and ripple.

Bithumb is contacting users who have not returned the assets individually to request their return.

A Bithumb official said, "If they do not comply with the return request, we will have no choice but to consider legal measures such as a civil lawsuit seeking return of unjust enrichment."

Legal circles and industry experts say a civil obligation to return the assets is likely to be recognized, but interpretations differ on whether criminal punishment such as embezzlement could apply.

The incident has put the exchange's weak internal control system under scrutiny.

Digital asset exchanges typically use an "ledger trading" method, recording figures first on the internal ledger before actual asset movement. Banks and securities firms in traditional finance also use this method.

The problem is that Bithumb's system failed to detect or block in advance an abnormal transaction size exceeding its actual holdings.

Financial authorities have begun assessing the incident and initiating sanction procedures. The Financial Supervisory Service sent an inspection team to Bithumb's headquarters on Feb. 7, a day after the incident, and is conducting an on-site inspection.

Financial Supervisory Service Governor Lee Chan-jin (이찬진) said on Feb. 9, "We are looking into whether this goes beyond a simple system error to involve weak internal controls and potential violations of law," adding, "If illegalities are found, we will immediately switch to a formal inspection and take strict measures."

The Financial Services Commission and the Financial Supervisory Service plan to urgently brief the National Assembly's Political Affairs Committee on Feb. 10 on the status of the Bithumb incident. The authorities will report comprehensively on the circumstances of the incident, the status of user 피해, and the scale of unrecovered assets, and discuss institutional improvements to prevent a recurrence.

In particular, the government and the ruling party are pushing a plan to impose high-level internal control obligations on digital asset exchanges on par with those of financial companies, using this incident as a catalyst.

The "Digital Asset Basic Act" currently being prepared is expected to include additional regulations such as establishing a real-time verification system between the ledger and actual held assets, mandating multiple confirmation procedures for large-scale asset movements, and introducing devices to control human error.

Lee said, "An absurd situation occurred where bitcoin, which is nothing more than virtual data, was cashed out without any control," adding, "Unless this problem is resolved, we will substantially strengthen the regulatory and supervisory framework so that it becomes difficult to license exchanges."