Philip Shaw, chief economist at Investec in London said Powell's testimony was unlikely to change from the one he delivered on Tuesday, putting the focus on the question and answer session.
It would appear markets are bracing for more hawkish commentary from Powell today when he appears before the Senate Banking Committee, once again discussing the semi-annual monetary policy report. For that reason, he said, the Fed does not feel it needs to speed up the pace of benchmark policy rate increases. The Fed raised its key policy interest rate three times last year and has signaled another three increases may be coming this year.
The Dow Jones Industrial Average fell 46.77 points, or 0.19 percent, to 24,982.43.
Powell was making his public debut as Fed chairman after succeeding Janet Yellen on February 5, with appearances before the House on Tuesday and the Senate today to deliver the central bank's semi-annual monetary policy report.
"With the economy set to receive an additional fiscal boost following the recent deal in Congress to raise the discretionary spending caps, we are revising up our GDP growth forecasts for both this year and next", the research firm said in a note. "Gradual" has been the operative word used by the central bank since it began raising rates under Powell's predecessor, Janet Yellen, in late 2015.
U.S. stocks have been under pressure since Powell's testimony Tuesday suggested the central bank could accelerate rate increases amid stronger growth and a resurgence of inflation.
"By continuing to gradually raise interest rates over time we are trying to ... achieve inflation moving up to target, but also make sure that the economy doesn't overheat", Powell said.
In his comments, Powell did not express worries that the economy was starting to overheat, stressing instead a number of developments showing economic strength. "We don't see any strong evidence yet of a decisive move up in wages". While saying it "seems to me we're very close to full employment", Powell also acknowledged that wages - while growing - have not been felt equally in the economy. "We've got an economy with strong momentum".
"I'll be honest, I would have thought you'd seen more wages increase by this point", Powell said during the hearing.
Rising inflation and bond yields were the main concerns as Wall Street ended a turbulent February on Wednesday, with the S&P 500 posting its first monthly loss in 11 months.
The central bank has been struggling with low inflation for years and despite ongoing evidence to the contrary, it continues to anticipate a near-term rise in prices.
Powell says that the government's tax and spending policies have also become more stimulative.
Markets will also watch for United States economic data, with personal consumption expenditure for January, the Fed's preferred measure of inflation, due at 3.30pm local time.