Bear Stearns Cos., the biggest broker for American hedge funds, offered to provide $1.5 billion in loans to help rescue a money-losing fund run by its asset-management unit, a person familiar with the situation said.

The plan calls for New York-based Bear Stearns to provide the money only if some of the hedge fund’s creditors, which include Merrill Lynch & Co. and JPMorgan Chase & Co., inject $500 million of cash into the fund, said the person, who declined to be named because the negotiations aren’t public.

Bear Stearns, seeking to stave off liquidation of the fund, made the commitment Monday in a meeting with creditors after losses forced the sale of $4 billion of mortgage bonds last week. Merrill Lynch and JPMorgan had planned to sell another $800 million of bonds of so-called collateralized debt obligations owned by the fund this week, the person said. The fund’s potential closure sparked concern about wider losses in the market for subprime-mortgage bonds and CDOs.

“It’s tough to tell whether this was an isolated event or whether there will be other funds like this that have bought this type of paper and are facing mark downs or redemptions,” a product portfolio manager who runs the CDO business at Chapel Hill, N.C.-based Smith Breeden Associates Inc, Peter Nolan, said. The firm manages about $34 billion in fixed-income assets, about a third of which are asset-backed bonds.

The banks may be considering a bailout because asset sales could force them to revalue their own investments and those of other funds they lend to, the managing director at New York-based investment-research firm Graham Fisher & Co, Josh Rosner, said.

“The value that assets are being carried at may well be proved to be far above” what they’re really worth, Mr. Rosner said.

Bear Stearns spokesman Russell Sherman didn’t immediately return calls seeking comment. A spokeswoman for New Yorkbased Merrill Lynch, Jessica Oppenheim, declined to comment, as did a spokesman for New Yorkbased JPMorgan, Brian Marchiony.