One of Japan's largest digital currency exchanges reports losing about $ 534 million (£ 380 million) of virtual money in a hacking attack on its network. This is Coincheck where deposits and withdrawals were suspended for all crypto-currencies except for Bitcoin as it assessed its losses in NEM, a lesser-known currency.
If the theft is confirmed, it will be the biggest loss for a digital currency ever.
Another Tokyo exchange, MtGox, collapsed in 2014 after admitting $ 400 million had been stolen from its network.
Money stolen from Coincheck is said to be kept in a "hot wallet" - an internet-connected part of the exchange. This contrasts with a cold wallet, where funds are securely stored offline.
Coincheck claims to know the digital address where the money was sent and will do whatever it takes to compensate investors.
What do we know about the hack?
The hackers raided the 02: 57 (17: 57 GMT) on Friday, the company said in a statement, but the violation was not discovered until 11: 25, about eight and a half hours later.
Company chief operating officer Yusuke Otsuka said 523 million NEMs were sent from Coincheck's NEM address during the breach.
"The figure is around 58 billion yen based on the rate calculation found," he said at a press conference on the Tokyo Stock Exchange.
Coincheck was still examining how many customers had been hit and trying to determine if the attack was launched from Japan or another country.
“We know where the funds have been sent,” Otsuka added. "We are tracking them and if we are able to continue monitoring, it may be possible to recover them, but that is something we are investigating at the moment."
Coincheck reported the incident to the police and the Japanese financial services agency.
The damage of the loss?
NEM, the tenth cryptocurrency by market value, fell 11% over a 24-hour period to 87 cents, starting at 18:30 pm, Bloomberg news agency reports.
Among other crypto-currencies, Bitcoin fell 3,4% and Ripple lost 9,9% on Friday, according to prices seen by the agency.
More was lost on Friday than the 2014, when MtGox lost what he thought was 850.000 bitcoin. However, MtGox later found 200.000 bitcoin in an old digital wallet.
After the collapse of MtGox that shook the digital currency world, a licensing system was introduced in Japan to increase the oversight of local currency exchanges such as Coincheck.
“What is the impact? It's hard to tell, ”Marc Ostwald, global strategist at ADM Investor Services International in London, told Bloomberg.
“Japan is one of the most pro-crypto trading countries among the G-20 countries. In Japan they don't really want a crackdown on that market.
What is Coincheck?
Founded in 2012, the company is headquartered in Tokyo, where it employed 71 people as of August last year.
Its headquarters are located in Shibuya district, a very popular area among start-ups that also hosted MtGox, according to Bloomberg.
Last year, Coincheck began running ads on national television with popular local comedian Tetsuro Degawa, the agency adds.