March 16 (Reuters) - The S&P 500 tumbled 8% at opening on Monday, triggering an automatic 15-minute halt of Wall Street's three main indexes for the third time in six days, as traders reacted to drastic weekend measures from the Federal Reserve to stave off a global recession.
The second emergency cut in interest rates by the U.S. central bank in a fortnight only added to the sense of panic among investors, worried that the coronavirus pandemic is paralyzing supply chains and squeezing company finances.
Latest economic figures from China earlier on Monday showed factory data plunging at its sharpest pace in three decades, underscoring the damage on the world's second biggest economy.
At 9:30 a.m. ET the Dow Jones Industrial Average was down 2,250.46 points, or 9.71%, at 20,935.16, the S&P 500 was down 220.55 points, or 8.14%, at 2,490.47 and the Nasdaq Composite was down 482.15 points, or 6.12%, at 7,392.73.
If the S&P 500 falls 13% once trading resumes, it will trigger a level-2 circuit breaker and halt trading again for 15 minutes. (Reporting by Shreyashi Sanyal in Bengaluru)