Shares in Borders have fallen 15% after the US bookselling group said it would delay payment to some publishers in a bid to preserve cash.
The company has been left short of money after its available credit under existing agreements was cut because the value of its inventories has fallen.
Borders said it was seeking to replace those credit facilities.
But if it failed to do so, the second largest bookseller in the US said it could face a "liquidity shortfall".
Company spokeswoman Mary Davis said that the firm would work with the publishers that supply it with books in order to restructure their payment arrangements.
Borders benefits from "vendor finance", by which suppliers provide the retailer with books for sale in its stores well in advance of receiving payment.
The company warned there could be "no assurance that it will be successful in refinancing its senior credit facilities or restructuring its vendor financing arrangements".
Failure to do so could leave the company without cash in the next three months.
Borders' latest figures showed losses doubled for the third quarter.
The company has said that it is in talks with other possible lenders to replace its financing, and that it may sell some assets to raise money.
It is also closing down certain stores to improve its position.
The company's competitors include fellow books specialists Barnes & Noble, as well as the giant retailers Amazon, Wal-Mart and Target.
Borders was recently approached by an activist investor, William Ackman, who owns 37% of the company and offered to finance a bid for its much larger rival, Barnes & Noble.
The electronic book market, spearheaded by Kindle, is a new battleground, although Borders has launched its own e-bookstore.
Borders sold its UK business in June 2007 to a private equity group. It went into administration in 2009.