Dec. 4 (Bloomberg) -- A21 Inc., an online digital-content company, sought bankruptcy protection from creditors with a plan to sell the U.S. assets of units SuperStock and ArtSelect.

The company listed assets of $25.2 million and debt of $30.3 million as of Sept. 30 in Chapter 11 documents filed today in U.S. Bankruptcy Court in Jacksonville, Florida, where it is based. SuperStock and ArtSelect also sought protection.

“It is very important to sell the businesses as quickly as possible because the companies operate at a significant negative cash flow,” the company said in court papers. ArtSelect had a net loss of $324,000 for the nine months ended Sept. 30. SuperStock had a net loss of $16,000 for the same period, court papers show.

A21 is an online marketplace of digital stock images. Its clients include artists, photographers, advertisers and publishers, according to court papers.

The company proposes to sell the SuperStock-owned photograph library and Web sites to Masterfile Corp. for $1.5 million. A21 agreed to pay as much as $500,000 for certain expenses related to contracts assigned to the buyer, which will reduce the net proceeds, court papers show.

ArtSelect proposes to sell all its assets to Metaverse Corp. for $700,000. SuperStock is seeking a purchaser of the stock of its U.K. subsidiary, which isn’t in bankruptcy, court papers show. The companies have asked for approval of procedures for an auction of the assets. Items not for sale include accounts receivable, cash, potential litigation claims, avoidance actions and claims for tax refunds.

The case is In re A21 Inc., 08-07610, U.S. Bankruptcy Court, Middle District of Florida (Jacksonville).

To contact the reporter on this story: Dawn McCarty in Wilmington, Delaware, at dmccarty@bloomberg.net.

Last Updated: December 4, 2008 12:30 EST