Mock Bitcoins are displayed on a table in an illustration picture
Mock Bitcoins are displayed on a table in an illustration picture Reuters

A mystery bidder has bought all 30,000 bitcoins seized from the notorious online black market Silk Road at an auction organised by the US Marshals Service (USMS).

The USMS said one bidder had won the entire amount, but did not reveal the bidder's identity.

The bitcoin collection is valued at $19.2m (£11m, €14m) based on current bitcoin market rates of about $640.

There were some 45 bidders registered for the online auction, with each putting down a deposit of $200,000. The auction drew 63 bids for 10 blocks of bitcoins. The winner was notified on 30 June and the bitcoins were transferred on 1 July.

SecondMarket, Pantera Capital, Binary Financial and Bitcoin Shop Inc had earlier revealed that they were participating in the auction.

Barry Silbert of SecondMarket, which runs a Bitcoin investment platform, said his firm was outbid. Hedge fund Pantera Capital said its bid was below the market price and was rejected. Bitcoin Shop revealed that its bid was also rejected.

Sil Road was taken down after US prosecutors arrested Ross William Ulbricht, its alleged owner and operator over suspicions of drug trafficking, computer hacking, money laundering and contract killings.

The website, which had a turnover of more than a million dollars a month, had been using bitcoin as its preferred mode of payment.

The prosecutors seized 29,000 bitcoins from the website, and a US judge signed a forfeiture order on the "proceeds of crime".