U.S. stocks pulled back from their recent record highs Monday, as big swings return to Wall Street at the onset of a year where the dominant expectation is for a powerful economic rebound to sweep the world.

The S&P 500, which ended 2020 at an all-time high, slid 1.5% after earlier dropping as much as 2.5%. It was the benchmark index's biggest decline since late October. Technology companies accounted for a big share of the sell-off, along with industrial, communication services, health care and other stocks. Only the S&P 500's energy sector managed to eked out a gain.

The selling comes as cor...