WASHINGTON — The Federal Reserve's new boss, Ben Bernanke, has the same concern as the old boss — that inflation could flare up. So interest rates are likely to move higher.

Bernanke, at his first meeting as Fed chairman, boosted borrowing costs to a five-year high and hinted that an additional interest rate increase could be in store. In doing so, Bernanke stuck to the script written by his predecessor, Alan Greenspan, who had run the central bank for 18 1/2 years.

"The more things change, the more they remain the same," observed economist Joel Naroff, president of Naroff Economic Advisors.

Wrapping up a two-day meeting yesterday, Bernanke and his Fed colleagues struck a mostly positive tone, saying the economy "rebounded strongly" in the January-to-March quarter from an end-of-year lull. But Fed policymakers raised concerns about the potential for inflation to take off.

In a unanimous decision, the Fed raised its key interest rate — the federal funds rate — by one-quarter of a percentage point, to 4.75 percent. This rate, which is the interest that banks charge each other on overnight loans, affects other rates charged to consumers and businesses.

Commercial banks reacted by lifting their prime lending rate — for certain credit cards, home equity lines of credit and other loans — by a corresponding amount, to 7.75 percent.

Both the prime rate and the funds rate are at their highest since spring 2001.

Bernanke presided over his first meeting of the Federal Open Market Committee, the group that sets interest rates, and continued the rate-raising campaign set in motion by Greenspan.

It was the 15th such increase since the Fed started tightening credit in June 2004.

On Wall Street, stocks tumbled as investors expressed disappointment that more rate increases could be in the offing. The Dow Jones industrials lost 95.57 points to close at 11,154.54.

Some economists and investors had hoped Bernanke would indicate that yesterday's increase was the last; he did not.

"The committee judges that some further policy firming may be needed" to keep inflation and the economy on an even keel, policymakers said in a statement after their meeting. That matched the language issued after the previous Fed meeting on Jan. 31.

Attention now turns to the next meeting, on May 10.

"The statement suggests that we will see another rate hike in early May to ensure that the inflation genie stays in the bottle," said Lynn Reaser, chief economist at Bank of America's Investment Strategies Group.

"The Fed under Mr. Bernanke gave some fairly clear guidance that the Fed is not yet quite through raising rates. But we do believe there is a light at the end of the tunnel," Reaser said.

Many economists believe the Fed's rate-raising campaign will end this year.

Bernanke took over the Fed on Feb. 1 after Greenspan's 18-plus-year run. Bernanke, who was an economics professor at Princeton and chairman of President Bush's Council of Economic Advisers, is leading the Fed at a time of concerns about the slowing housing market and bloated budget and trade deficits.

For now, though, Bernanke's message on the economy is mostly encouraging. "He's saying the economy is healthy — inflation is OK for now, but it could become a problem, so we're not done raising rates yet," said Stuart Hoffman, chief economist at PNC Financial Services Group.