U.S. regulators have asked some banks to take more deposits from large investors even if it's unprofitable, and lenders in return are seeking relief on insurance premiums and leverage ratios, according to six people with knowledge of the talks.

Deposits are flooding into the biggest U.S. banks as customers seek shelter from Europe's debt crisis and falling stock prices. That forces lenders to raise capital for a growing balance sheet and saddles them with the higher deposit insurance payments. With short-term interest rates so low, it's hard for financial firms to reinvest the new money profitably.

Regulators have asked banks to take the deposits anyway, three people said, with one lender accepting $100 billion. The regulators want lenders to take the deposits because it improves the stability of the financial system, according to one of the people, who said U.S. banks are viewed as places of strength.