Current bids for Refco's (RFX) futures brokerage business are likely to be around $1 billion, sources familiar with the bidding said on Monday.

Refco (search), which filed for bankruptcy last month after an accounting scandal, said on Friday that five bidders were vying for company assets.

Refco will approve bids by 5 p.m. (EST) Monday and will conduct an auction for the assets on Wednesday. By Thursday the company will submit winners to the bankruptcy court.

Ahead of the bid approval Refco's bonds traded at 77 cents on the dollar, hovering around their highest level since Oct. 11, before Refco filed for bankruptcy.

Suitors have not publicly discussed their offers so far.

In an earlier bidding war last month, before potential buyers had carefully examined the company's assets, privately held Interactive Brokers Group (search) said it would bid $858 million for the assets. That topped a joint bid from the Dubai government's investment arm and buyout firm Yucaipa Companies worth $828 million.

But those offers have risen as possible buyers have learned more about the company's assets, a source said.

Alaron, a Chicago futures and options broker, had submitted a bid for Refco Inc.'s private client business, an Alaron spokesman said on Monday.

Because Alaron's is only bidding for Refco's private client business, its bid was much smaller than the figures mentioned last month for Refco's entire futures business.

Man Group Plc (search), a London-based hedge fund company and broker, has also identified itself as one of the bidders.

In addition to Man and Alaron, sources close to the matter have told Reuters U.S. private equity firm J.C. Flowers & Co. and U.S. broker-dealer Interactive Brokers Group also submitted bids.

Man Group said in a statement it had bid for some of Refco's operations and assets, but did not provide details.

Refco plunged into bankruptcy after its chief executive, Phillip Bennett, was charged with securities fraud, which caused customers to abandon the company.