WASHINGTON - The Federal Reserve, confronted with a global stock sell-off fanned by increased fears of a recession, cut a key interest rate by three-quarters of a percentage point on Tuesday, the biggest one-day move by the central bank in recent memory.

The Fed said it was cutting the federal funds rate, the interest that banks charge each other on overnight loans, to 3.5 percent, down by three-fourths of a percentage point from 4.25 percent.