Blackstone Group is the likely front-runner for Citigroup Inc.'s Egg Banking PLC with the bid deadline arriving Thursday, people familiar with the situation said Wednesday.
It is unclear whether other potential bidders, such as Barclays PLC and TPG, remain interested.
Citigroup bought Egg for $1.13 billion from U.K. insurer Prudential PLC in 2007 and is selling the Internet bank as part of its strategy to reduce assets that aren't central to its business. It has already sold several of its alternative investments, including hedge fund, private equity and mezzanine interests.
Blackstone is working on a plan to buy Egg together with private equity-owned credit card company SAV Credit.
While Egg has a broad range of products, including savings accounts, loans and insurance as well as credit cards, SAV Credit's main focus is credit cards, which it supplies to more than 600,000 customers.
Any deal involving both Egg and SAV would create one of the U.K.'s largest credit-card companies.