The programs, Sullivan writes, were introduced back in the late 1970s. Instead of letting extra cash sit in customers' accounts, the brokerages would periodically place the money in money market accounts. The programs were modified in the 1990s to allow customers an opportunity to put their extra cash in bank accounts affiliated with the brokerages, instead of money market accounts. The modification of the program was the focus of the complaint filed against Merrill Lynch, Morgan Stanley, Citigroup, Charles Schwab, and Wachovia. Customers alleged that the brokerages at first paid customers who put their cash in broker-affiliated bank accounts interest rates similar to those they were offered in money market accounts. But subsequently, plaintiffs alleged, the brokerages began to pay lower rates--and also sought to limit customer access to money market accounts. Among other things, the plaintiffs claimed that the brokerages' disclosures about their cash sweep programs were inaccurate and that the brokerages owed their customers a fiduciary duty to place their extra cash in the highest interest-bearing account. The amount that such practices affected? A whopping $186 billion, according to the plaintiffs.

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