Markets were encouraged by Powell's comments on the economy. The Dow closed about 45,000 for first time ever, while the S&P 500 and Nasdaq also hit records.

The well-received results from Salesforce.com are having an outsized impact on the Dow -- the software maker's current premarket price equates to a 273-point boost to the blue-chip index, which remember is price-weighted.

Technology stocks pulled Wall Street to another record amid a mixed Monday of trading. The Standard & Poor's 500 rose 0.2% from its all-time high set on Friday to post a record for the 54th time this year.