The Fed announced that it was raising its target for the federal funds rate, the interest that banks charge each other, by a quarter-point to 2.5 percent. Before the Fed began tightening credit last June, the funds rate had been at a 46-year low of 1 percent.
The February increase is not expected to be the last. Analysts think the Fed will push the funds rate up in quarter-point increments through most of this year.
That would mean higher borrowing costs for consumers and businesses. The Fed's action on Wednesday was expected to be quickly followed by announcements from commercial banks that they were raising their prime lending rates, currently at 5.25 percent, by another quarter point as well.
In explaining its action, the Fed repeated a previous promise that it believed it would be able to raise rates at a "pace that is likely to be measured."
Analysts believe the Fed will keep raising rates in small quarter-point steps as long as there are no signs that inflation is becoming a problem.
Consumer prices rose by 3.3 percent last year, compared to a 1.9 percent rise in 2003. It was the biggest annual increase since 2000, but it was driven by a surge in energy prices. Inflation pressures are expected to moderate this year, helped by an expected continued decline in global oil prices.
The Fed's goal is to move the funds rate from an accommodative stance, where it is still stimulating extra economic growth, to a neutral stance where the funds rate is neither stimulating growth nor holding the economy back.
"The Fed is taking its foot off the accelerator without hitting the brakes," said Richard DeKaser, chairman of an American Bankers Association panel of economists that meets twice a year with Fed policy-makers to give them their views of where the economy is headed.
There is debate in economic circles about where the neutral level is, but many economists believe it is somewhere between 3.5 percent and 4.5 percent for the federal funds rate.
If the Fed keeps increasing rates by a quarter-point at each of the eight scheduled meetings this year, the funds rate would be at 4.25 percent at the end of this year, a level where many analysts believe Greenspan will feel good about stepping down in January 2006 when his term as a Fed board member ends.