Rebounding tech stocks are driving U.S. indexes higher Tuesday, a day after they tumbled on doubts about whether the artificial-intelligence frenzy really needs all the dollars being poured into it. The S&P 500 was 1% higher in late trading and clawing back nearly two-thirds of its earlier drop.

That bounce comes after stock plunged 17% on Monday and slashed more than $595 billion from the company's valuation, the biggest single-day market cap decline on record. But retail investors bought the dip at a record level, even as the sell-off gripped Wall Street, according to Vanda Research.