A bidding syndicate organized by Bitcoin Investment Trust and the trading division at SecondMarket has been revealed as the winner of nearly all of the 50,000 BTC auctioned by the US Marshals Service (USMS) last Thursday.

The syndicate won 19 of the 20 blocks put up for auction by the USMS, or a total of 48,000 BTC (worth roughly $16.6m at press time). The 50,000 BTC confiscated from alleged Silk Road leader Ross Ulbricht and sold were divided into 10 blocks of 2,000 BTC and 10 blocks of 3,000 BTC.

Bitcoin Investment Trust announced the news on Twitter, while the USMS separately confirmed the announcement in an email.

Brendan O’Connor, managing director at SecondMarket, told CoinDesk that he was pleased with the results the syndicate was able to provide its participants.

"We're very excited that the work that we put in in terms of organising the syndicate was able to bear some fruit this time around," he said.

Draper Fisher Jurvetson managing director and avid bitcoin enthusiast Tim Draper was revealed as the winner of a smaller block of 2,000 BTC (worth roughly $750,000 at press time) last Friday. Draper purchased 29,656 BTC seized from the now-defunct online black market Silk Road in June, announcing at the time that the bitcoins would be used to help bitcoin exchange Mirror (formerly Vaurum) serve more global consumers.

The auction was held over a six-hour period beginning at 8:00am EST and ending at 2:00pm EST. The USMS announced last week that just 11 registered bidders participated in the auction, down from the 45 observed during its first bitcoin auction in June.

Though overall bidder registration was down, participation in bidding syndicates appears to have increased. SecondMarket chairman Barry Silbert took to Twitter to reveal that 104 bidders participated in the auction group led by Bitcoin Investment Trust and SecondMarket, a figure that was up from 42 in June.

As a result, the 48,000 BTC will be divided among the 104 participants in the syndicate.

"The bitcoin were won by folks who participated in the syndicate, so we don't know what the plans are for the bitcoin," O'Connor added.

Bitcoin Investment Trust is the private, open-ended trust invested exclusively in bitcoin and helmed by investor and bitcoin enthusiast Barry Silbert, while SecondMarket provides an illiquid asset exchange marketplace.

Confirmed participants at the event included Binary Financial, Bitcoin Investment Trust, Bitcoins Reserve, Mirror (formerly Vaurum) and Pantera Capital.