British bank Northern Rock said it continues to work with a number of companies as part of its strategic review and has developed structures to allow it to seek interest from other parties.
Northern Rock, which is widely expected to be taken over after being provided emergency loans by the Bank of England after a funding crisis, said on Wednesday the talks were "complex" and "at an early stage."
"All proposals the company has received so far are preliminary in nature," it said in a statement.
It confirmed that buyout firm The Blackstone Group will not take part in a bidding process, after being appointed as an adviser alongside Merrill Lynch and Citi . Blackstone will be involved in future funding arrangements and the potential reconfiguration of its balance sheet, it said.
A Virgin Group-led consortium and U.S. buyout firm JC Flowers have confirmed they are considering a takeover. Cerberus, another U.S. buyout firm, is also casting an eye on the bank, sources familiar with the matter have said.
Northern Rock said the strategic review will be completed by February and further announcements will only be made when there is greater clarity or significant progress.
Analysts said the company's future is hard to predict, and its shares remain volatile.
"With a standalone future looking extremely unlikely any valuation for the group is increasingly dependent on the nature of a deal that can be struck with one of several potential suitors," Stephen Andrews, analyst at UBS, said in a research note on Wednesday.
The bank cut its target on Northern Rock shares to 195 pence from 445p, based on a probability weighted valuation tied to four possible outcomes for shareholders.
It said the value of Northern Rock's equity could be wiped out; shareholdings could be diluted due to a capital injection by a third party; it could receive a bid at a big discount; or funding could be found to allow the group to be wound down, which could value shares at around 295p apiece.
Northern Rock shares were up 0.3 percent at 183.9 pence, valuing it at just under 800 million pounds ($1.66 billion).