The turnabout has caught Wall Street's biggest banks off guard and is increasingly leaving them on the hook for funding takeovers that investors want little part of. On Tuesday, Bank of America Corp. and Morgan Stanley were forced to shelve the debt package backing the year's largest leveraged buyout -- $5.5 billion meant to fund Carlyle Group LP's purchase of Veritas, Symantec Corp.'s data-storage business, according to two people familiar with the matter.

"There's a risk of this happening more," said Jamie Farnham, who manages about $6 billion of high-yield bonds and leveraged loans for Los Angeles-based TCW Group Inc. "The amount of the market that is un-financeable is getting larger."

Fixed-income investors are fast pulling down the shutters on the riskiest deals as they brace for the Federal Reserve to raise the benchmark rate for the first time in almost a decade and the outlook for global growth darkens. That has left banks grappling with more than $15 billion of deals that money managers have rejected or demanded huge discounts to buy in recent weeks. Skittish investors could also cause those banks to think twice about putting together deals with high leverage in the future.

Bank of America and Morgan Stanley made significant revisions to the terms of the Veritas offering to entice investors, according to the people, who asked not to be identified because the information isn't public. It didn't work, leading the banks to postpone the offering in hopes of bringing it back when market conditions are more amenable, the people said.