Twice the Fed had cut rates this year and officials suggested in October that might be enough for the year to help the economy survive all that stress. Then the problems snowballed, leading Fed Chairman Ben Bernanke to sign that one more cut might be needed.

Analysts expect the Fed to trim its key rate, now at 4.5 percent, by one-quarter of a percentage point at the meeting Tuesday. Some even speculate about the possibility of a half-point cut.

Banks, financial companies and other investors who made loans to people with spotty credit or put money into securities backed by those subprime mortgages have lost billions of dollars. Investors in the U.S. and abroad have grown more wary of buying new debt, thereby aggravating the credit crunch.