(Bloomberg) ? Dubai?s government and California billionaire Ronald Burkle offered about $828 million for Refco Inc.?s regulated brokerage unit, topping two earlier bids. Investors including Leon Black said they may join an auction for the failed company.

Refco does business in the US, Canada, Bermuda and Europe and the company lists its Bermuda office as a private mail box at 48 Par-la-Ville Road, the offices of Mailboxes Unlimited.

A group led by Dubai and Burkle made the proposal during a bankruptcy court hearing in New York yesterday. A unit of Man Group Plc, the world?s largest publicly traded hedge fund company, New York-based Marathon Asset Management, and Black?s Apollo Management LLC said they?re potential bidders for all of part of New York-based Refco.

The new offer may derail Refco?s agreement last week to sell the futures business to J.C. Flowers & Co. for $768 million. More than 100 lawyers packed Judge Robert Drain?s courtroom yesterday, signalling that Refco?s assets may yet draw higher bids.

?There?s been a heightened level of interest in distressed assets and a lot of money going into them, so you?d expect to have multiple bidders,? said Jennifer Chien, who helps manage $50 billion at PNC Advisors in Philadelphia.

Refco was the largest independent US futures firm as recently as two weeks ago, with a market value of $3.6 billion. The company filed for bankruptcy on October 17 after disclosing a week earlier that chief executive officer Phillip Bennett, 57, covered up $430 million in uncollectible debt.

Bennett was charged on October 12 with securities fraud, prompting an exodus of customers and employees.

The Dubai-led offer also exceeds a $790 million bid last week by Interactive Brokers Group LLC, the largest independent US broker-dealer. It?s ?more favourable to the debtors and their estates? because of the higher value and lack of a break-up fee, DIGL Inc., a Delaware company formed by Dubai Investment Group LLC and Burkle?s Yucaipa Cos., said in court papers.

Refco?s creditors are owed $16 billion, according to the company?s estimate as of the end of August.

Arthur Hahn, a lawyer for Greenwich, Connecticut-based Interactive said in an interview that his client will increase its bid. He declined to be more specific.