Candover, the venture capitalist, has been tipped as favourite to buy Whitbread's 3,000 pubs for up a price of up to £1.5bn.
It is one of six companies invited to bid in the second round.
The others are Nomura, described as a strong number two, WestLB, L&G Ventures and Pubmistress, which only wants the leased estate.
Whitbread is thought to prefer a financial buyer that could take over the total estate.
Candover and L&G Ventures are in talks about a joint £600m bid for 990 Bass pubs. The two could combine the Bass and Whitbread pubs to establish a new independent pub giant.
However, Bass's plans for a sale are thought to have run into problems over bank financing after Morgan Stanley Dean Witter and Citibank were reported to have scaled back the amount they were willing to lend to prospective buyers by up to £150m.
Bidders, which include Nomura, are also thought to be concerned about the number or redundancies that would have to be make across the Bass estate.
Bass is proposing that the sites are converted from managed houses to tenanted and bidders are worried about finding the tenants needed to run the pubs and the time it would take to convert them.
It is one of six companies invited to bid in the second round.
The others are Nomura, described as a strong number two, WestLB, L&G Ventures and Pubmistress, which only wants the leased estate.
Whitbread is thought to prefer a financial buyer that could take over the total estate.
Candover and L&G Ventures are in talks about a joint £600m bid for 990 Bass pubs. The two could combine the Bass and Whitbread pubs to establish a new independent pub giant.
However, Bass's plans for a sale are thought to have run into problems over bank financing after Morgan Stanley Dean Witter and Citibank were reported to have scaled back the amount they were willing to lend to prospective buyers by up to £150m.
Bidders, which include Nomura, are also thought to be concerned about the number or redundancies that would have to be make across the Bass estate.
Bass is proposing that the sites are converted from managed houses to tenanted and bidders are worried about finding the tenants needed to run the pubs and the time it would take to convert them.
