U.S. stocks fell again following a sell-off that swept Europe and Asia. The S&P 500 sank 0.8% Tuesday after earlier dropping as much as 1.5%. The Dow Jones Industrial Average fell 1.1%, and the Nasdaq composite sank 1.2%. Nvidia was again the heaviest weight on the market as worries continue that its price shot too high in the frenzy around artificial-intelligence technology. Bitcoin, another former high-flyer, briefly dropped below $90,000. Stock indexes fell around the world as questions rise about whether stocks have broadly become too expensive and whether the Federal Reserve will keep cutting interest rates.