The Dow ticked up less than two-tenths of a percent, the S&P 500 ticked down two-tenths and the Nasdaq shed one-tenth of a percent.

At a Q&A session in Washington, Powell said recent inflation data has not given policymakers enough confidence to lower borrowing costs any time soon.

But Kevin Nicholson, global fixed income chief investment officer at RiverFront Investment Group, said that while that's brought Wall Street's main indexes down from their "sugar highs," strong corporate earnings should continue to power stocks.

"Stocks will ultimately end up reacting to earnings. But right now, because we're still at the very early stages of earnings season, there hasn't been that many companies to report. So, at this point, the news headlines are geared towards the Fed. However, we believe that you're going to see a strong earnings season, because of the growth that we've seen in the overall economy."

Among those reporting strong earnings: Morgan Stanley, whose shares rose 2.5% after its first-quarter profit beat estimates on resurgent income from investment banking.

Bank of America, however, dropped 3.5% after the lender posted lower first-quarter profits as its loan loss provisions grew.

Johnson & Johnson slipped more than 2% as the drugmaker's revenue missed analysts' estimates after sales from its blockbuster psoriasis drug, Stelara, fell short of expectations.

And Tesla shares slipped more than 2.5% a day after falling over 5% on news that the EV maker plans to lay off more than 10% of its global workforce.