BlockBeats news, on February 7, South Korea's second-largest cryptocurrency trading platform Bithumb mistakenly airdropped a total of 620,000 bitcoins (2.95% of BTC total supply) to 695 customers yesterday due to a staff error. Although the platform has almost fully recovered the losses (only 0.3% remains unrecovered), the platform's action of over-allocating 620,000 bitcoins still triggered heated discussions in the community about "ghost balances on CEX."
It is known that Bithumb has not directly disclosed detailed BTC reserve amounts or complete on-chain Proof of Reserves (PoR) evidence. However, prior to this, the Korean media MK.co.kr clearly wrote in its report that as of the end of last third quarter, Bithumb held and safeguarded 42,619 bitcoins. Even if the BTC reserves increased afterward, they would certainly be far less than 620,000 in quantity.
This incident is clearly an internal ledger error, not an actual airdrop of 620,000 BTC from a hot wallet or on-chain. The extra BTC in user accounts is "ghost balance," and the platform does not actually hold that much BTC to support withdrawals. Therefore, when some users dumped it, the price crashed instantly, but there was no large-scale on-chain transfer.
It is worth noting that almost all major CEXs do not record each user's transaction in real-time on the blockchain, but instead use internal databases/ledgers (centralized ledgers) to manage user balances. This means the "balance" users see is mainly an internal record, not a real-time on-chain balance. Only when users withdraw funds does real on-chain data change occur. Most CEXs have risk control, multiple reviews, and automated verification to prevent extreme errors. Bithumb has exposed an internal control vulnerability (employees can directly modify large reward units), and South Korean regulators have already intervened in the investigation.