Likely buyers could include media firms, music retailers, record companies or venture capitalists.

The asking price is $25m (£16m) and the deadline for any bids is 21 August ahead of a 27 August auction.

The German publishing major Bertelsmann remains keen to buy the assets and has vowed to raise its bid by $9m to a total of more than $100m.

Other bidders

A committee of Napster creditors hopes that the auction will bring in other investors.

Bertelsmann is among Napster's creditors since the German giant has lent Napster more than $85m.

Bertelsmann is also funding Napster's operations during a restructuring which followed its recent application for bankruptcy protection.

The $85m loan would form part of Bertelsmann's bid.

But if the bankruptcy judge decides to disregard the loan, other bidders could gain control of Napster for, perhaps, as little as $25m.

Fallen giant

At its height, Napster was an immensely popular site among technology-savvy music fans who swapped digital files containing songs.

But it also became the focus of anger and legal action from record companies and some musicians who accused it of letting fans cheat them out of royalty payments.