A South Korean cryptocurrency exchange apologised on Saturday after mistakenly transferring more than $40 billion worth of bitcoin to users, which briefly prompted a selloff on the platform.

Bithumb said it accidentally sent 620,000 bitcoins, currently worth more than $40bn, and blocked trading and withdrawals for the 695 affected users within 35 minutes after the error occurred on Friday.

According to local reports, Bithumb was meant to send about 2,000 South Korean won ($1.37) to each customer as part of a promotion, but mistakenly transferred roughly 2,000 bitcoins per user.

“We sincerely apologise for the inconvenience caused to our customers due to the confusion that occurred during the distribution process of this (promotional) event,” Bithumb said in a statement.

The platform said it had recovered 99.7 per cent of the mistakenly sent bitcoins, and that it would use its own assets to fully cover the amount that was lost in the incident.

It admitted the error briefly caused “sharp volatility” in bitcoin prices on the platform as some recipients sold the tokens, adding that it brought the situation under control within five minutes.

Its charts showed the token’s prices briefly went down 17pc to 81.1 million won on the platform late Friday.

In a separate statement released later on Saturday, Bithumb said some trades were executed at unfavourable prices for users due to a price drop during the incident on Friday, including “panic selling”.

The platform said it would compensate affected customers, covering the full price difference as well as a 10pc bonus.

It estimated losses at about 1bn won.

The platform earlier stressed that the incident was “unrelated to external hacking or security breaches”.

Bitcoin, the world’s biggest cryptocurrency, sank this week, wiping out gains sparked by US President Donald Trump’s presidential election victory in November 2024.