The US Marshals Service (USMS), the federal agency charged with managing the sale of property confiscated by federal law enforcement agencies, has released new data on its auction of 50,000 BTC confiscated from alleged Silk Road head Ross Ulbricht and held today.

The USMS data, distributed via email, indicates that the number of bidders in the agency's second bitcoin auction has declined significantly from the first auction held this June.

That auction, which received widespread media coverage in the US and had an observable affect on bitcoin's market, attracted a total of 45 registered bidders, who placed 63 bids over the course of the auction. By contrast, 11 registered bidders participated in today's auction, submitting a total of just 27 bids.

Overall, the number of registered bidders decreased 75% from the first auction, while the number of bids fell 57%.

The USMS indicated that it had no further information regarding the auction or any winning bidders to release at the time it issued the finding, stating:

Notably, the 50,000 BTC (worth roughly $18.6m at press time) is only part of a larger sum of bitcoins taken from Ulbricht at the time of his arrest in October 2013. An additional 94,000 BTC will be auctioned off by the USMS in the coming months, the agency has stated, though the dates for these events have not yet been issued.

Perhaps accounting for the difference in participation observed between the events was the shorter auction period.

Today's auction began at 8:00 am and ended at 2:00 pm EST, providing bidders a six-hour window within which to submit bids. By contrast, the agency's first bitcoin auction, held 27th June, allowed bidders a 12-hour window, from 6:00 am to 6:00 pm EST.

Additionally, members of bitcoin's investment community had earlier reported a decline in interest among their clients. For example, Binary Financial managing partner Harry Yeh told CoinDesk that he believes the decline is indicative of an overall decrease in the difficulty associated with purchasing large blocks of bitcoin on the open market.

The decline could also reflect increased participation in bidder syndicates assembled by companies in the bitcoin industry. For example, 42 bidders participated in a syndicate headed by illiquid asset marketplace provider SecondMarket in June's auction. Thursday's auction saw at least two syndicates participate, including those launched by the Bitcoin Investment Trust and the trading desk at Digital Currency Group and Mirror.

Previously announced participants in the auction include Binary Financial, Bitcoin Investment Trust, Bitcoins Reserve, Mirror (formerly Vaurum) and Pantera Capital.

At press time, the USMS auction seemed to have little affect on the price of bitcoin, which was down nearly 1% on the CoinDesk US Bitcoin Price Index (BPI).

The price of bitcoin also experienced only slight fluctuations over the course of the day, opening at $374.97 and moving between a high of $378.11 and a low of $367.44.

By contrast, June's event coincided with a more tumultuous day in the bitcoin markets, with the price rising 7%, a factor that could be attributed to the bullish sentiment in the community following the successful sale.

Overall, the price of bitcoin has declined from roughly $640 at the time of June's action to a press time total of $371.81 today.

Images via USMS; Shutterstock