About 25 minutes into trading, the Dow Jones Industrial Average was at 21,505.07, down more than 2,000 points or 8.7 percent.
Trading was suspended after losses hit seven percent on the S&P 500, a benchmark that triggers circuit breakers halting transactions to manage crises. The NBA suspended its professional basketball season after a player tested positive, while Carnival announced that its Princess cruise line would suspend service for 60 days.