Citigroup's attempts to sell its CitiFinancial unit have hit a stumbling block as potential bidders remain uncertain about the unit's funding as a standalone business, the Financial Times reported, citing people familiar with the matter.

CitiFinancial, one of the largest U.S. consumer finance companies, was put up for sale as Citigroup tightened its focus on wealthier, more credit-worthy clients.

In March, Reuters reported the company might retain a stake in the unit and would offer partial financing to bidders, who included the Who's Who of the private equity world.

Potential buyers are waiting for reviews by credit rating agencies, which are expected to report on the units finances in next two weeks, the business daily reported.

Citi also plans to produce audited financial statements on the standalone unit and has not made it clear how large a funding gap it would be prepared to fill, the paper said.

Three groups remain in the sales process -- Blackstone, Carlyle, and Brysam Global Partners form one group, Apollo Management and JC Flowers form a second bidding group, while Centerbridge Capital Partners leads a third -- the Financial Times said.

Citigroup declined to comment.

The CitiFinancial business has a book value of about $2 billion, and comes with some $13 billion of assets.

Citigroup is looking to sell the business without taking losses, unlike insurer American International Group Inc , which last year sold its consumer finance business at a loss.

(Reporting by Jochelle Mendonca in Bangalore, editing by Bernard Orr)