As the WSJ reports, far from paying for the privilege of holding other people's cash (and why would they with nearly $3 trillion in positive carry excess reserves sloshing around) US banks - primarily of the TBTF variety - "are urging some of their largest customers in the U.S. to take their cash elsewhere or be slapped with fees, citing new regulations that make it onerous for them to hold certain deposits."

The change upends one of the cornerstones of banking, in which deposits have been seen as one of the industry's most attractive forms of funding, said more than a dozen corporate officials, consultants and bank executives interviewed by The Wall Street Journal.

U.S. banking rules set to go into effect Jan. 1 compound the issue, especially for deposits that are viewed as less likely to stay at the bank through difficult times.

The new U.S. rules, designed to make bank balance sheets more resistant to the types of shocks that contributed to the 2008 financial crisis, will likely have little effect on retail deposits, insured up to $250,000 by federal deposit insurance. But the rules do affect larger deposits that often come from big corporations, smaller banks and big financial firms such as hedge funds. Hundreds of companies and other bank customers with deposits that exceed the insurance limits could be affected by the banks' actions.

Overall, about $4 trillion in deposits at banks in the U.S. were uninsured, covering more than 3.5 million accounts, according to Federal Deposit Insurance Corp. data

The rule primarily responsible involves the liquidity coverage ratio, overseen by the Federal Reserve and other banking regulators. The new measure, finalized in September, as well as some other recent global regulations, are designed to make banks safer by helping them manage sudden outflows of deposits in a crisis. The banks are required to maintain enough high-quality assets that could be converted into cash during a crisis to cover a projected flight of deposits over 30 days.

Because large, uninsured deposits would be expected to leave most quickly, the rule will now require that banks maintain reserves that they cannot use for profitable activities like making loans. That makes it much less efficient or profitable for banks to hold these deposits.

Some argue that while it is a good policy on its face, the rule potentially magnifies problems in a recession by encouraging banks to hoard high-quality assets, potentially paralyzing markets for these assets such as Treasury securities and some corporate bonds.

"This proposal, which is supposed to promote financial stability, actually does the opposite," said Thomas Quaadman, a vice president at the U.S. Chamber of Commerce.