New economic data reignited concerns about the health of the economy, with U.S. stocks off to a rocky start to September and technology stocks collectively tumbling. The Dow fell more than 650 points, or 1.6 percent, during the session. The S & P 500 fell more than 2.2 percent, while the fear gauge VIX surged 30 percent. The Nasdaq fell 3.3 percent, its worst day since the Aug. 5 global stock market rout. Shares in artificial intelligence darling NVIDIA (NVDA. O), which has been on investors' radar for more than a year, fell more than 9 percent, leading semiconductor stocks to pressure the stock market. Earlier data showed that the final U.S. S & P global manufacturing PMI fell in August, while the U.S. ISM manufacturing index in August also missed economists' expectations. Larry Tentarelli, chief technology strategist at Blue Chip Trends, said: "The market seems to be very sensitive to any data right now." "We've become a very data-dependent market."