Stocks started the week with a bang as bargain hunters swooped in following last week's broad-market thumping. Monday's impressive gains came even as Nvidia ( NVDA ) — one of the world's biggest companies by market cap — plunged on reports that the artificial intelligence chipmaker's CEO, Jensen Huang, is being investigated over his relationship with a woman suspected of being a Chinese spy.

At the close, the blue-chip Dow Jones Industrial Average was up 2.2% at 52,389 and the broader S&P 500 was 2.4% higher at 7,549. The tech-heavy Nasdaq Composite gained 2.7% to 25,253, exiting correction territory .…