There is a feud brewing between those Wall Street firms that have agreed to buy back auction-rate securities and those that haven't.

In recent weeks, UBS, Citigroup, JP Morgan Chase & Co., Morgan Stanley, Merrill Lynch & Co. and Wachovia Corp. have agreed to buy back more than $40bn ($27.2bn) of auction-rate securities from their clients, including individuals, charities and small-business investors.