FRANKFURT, Germany - The European Central Bank pumped a record $502.5 billion into money markets yesterday to keep banks from Finland to France flush with cash.

The surprise infusion, along with another liquidity injection by the Bank of England, was aimed at keeping jittery markets calm amid a credit squeeze sparked by the U.S. subprime-mortgage crisis. It seemed to be working, with stock markets stable after a global slide Monday.

Banks have been afraid to lend one another money for their short-term needs amid a scarcity of credit, driving up interest rates. The central banks are sharply stepping up their normal role as providers of liquidity, a job that usually gets far less attention than their interest-rate moves.

The ECB oversees monetary policy among the 13 nations that use the euro. It pledged to satisfy any and all bids from banks willing to pay interest on loans at or above 4.21 percent. The ECB said 390 banks and financial institutions submitted loan bids totaling $542.76 billion at rates of 4 percent to 4.45 percent.

Brian Dolan, director of research at Gain Capital Group L.L.C., said the massive ECB liquidity injection "resonated with the markets because of its size. It satisfied a lot of the funding needs we will have over the rest of the year."

Dolan said the ECB's effort was far more reassuring to investors than a much smaller $20 billion Federal Reserve auction for commercial banks held Monday. The results of the Fed auction will not be known until today, a delay that likely increased anxiety for auction participants.

The ECB move lifted investor confidence on global stock exchanges yesterday, contrasting with a Monday sell-off after the Fed action.

But, warned Tony Crescenzi of Miller Tabak & Co. L.L.C., the large amount sought by banks may lead to fears that funding needs were still problematic.

Also yesterday, the Bank of England said it would offer additional reserves to lenders as part of the global attempt to tackle the deepening credit crisis.

The bank said it had allotted $20.18 billion in three-month funds, with a weighted average rate of 5.9 percent.