Stocks fell on Tuesday as technology stocks struggled and traders prepared for a potentially difficult month.

The Dow Jones Industrial Average 450 points or 1.1% lower. The S&P500 fell by 1.1%, while the Nasdaq-Composite fell by 1.4%.

Stocks came under downward pressure when NVIDIAthe high-flying artificial intelligence darling that has captured investors’ attention for more than a year, lost more than 4%. It was one of several semiconductor stocks, including micron, UCK And Advanced micro devices Declines in the session. The VanEck Semiconductor ETF (SMH) fell by more than 3%.

The market also fell on Tuesday morning after two measures of manufacturing production showed signs of weakness, reigniting concerns about slowing growth in the U.S. economy. The S&P Global index fell from July to August, while the Institute for Supply Management index came in below the level expected by economists surveyed by Dow Jones.

Tuesday’s moves kick off a new trading month after the three major averages ended August with gains. U.S. markets were closed Monday for the Labor Day holiday.

But the momentum that stock prices experienced in September was not always to be expected. Concerns that the US economy could slide into recession and the unwinding of a popular hedge fund trade involving the Japanese yen caused stock prices to plummet in early August. The S&P 500 lost more than 7 percent at one point before recovering.

The move comes ahead of the first major economic report of the month on Friday, when the U.S. government releases the August employment report. Wall Street will also face seasonal headwinds, with September on average the worst month for the S&P 500 in the past decade.