His comments came after a strong jobs report last week stymied rising hopes of less aggressive monetary policy.
The Nasdaq and the S&P 500 fluctuated during and after Powell's remarks.
Boosting the tech-heavy Nasdaq (.IXIC) and the S&P 500 (.SPX) was Microsoft Corp (MSFT.O).
Six of the top 11 sectors on the S&P 500 fell, but technology (.SPLRCT) was among top gainers, up 1.61%.
So far, more than half of the companies on the S&P 500 have reported quarterly earnings, with 69.1% of them beating expectations, according to Refinitiv.