The U.S. stock market on Wednesday morning is facing a pullback ahead of the Federal Reserve's updated policy statement. However, a measure of the market was showing signs of panic-like selling behavior, even as a rally in the technology-related sector was helping propel tech-pegged indexes to new records. The Arms Index, a volume weighted breadth measure that tracks the ratio of advancing stock to declining stocks over the ratio of advancing volume over declining volume, was showing a reading of 2.318 for the New York Stock Exchange-listed shares. Many technicians say a rise to at least 2.000 suggests panic-like selling behavior. At last check, the ARMs index showed that declining volume was 91.4% of total volume on the NYSE, with declining shares outpacing advancers at a ratio of 4.7 to 1. The Arms Index reading comes as the Dow Jones Industrial Average DJIA, -0.53% was down 318 points, or 1.2%, at 26,976, while the S\&P 500 SPX, -0.21% was off 0.7% at 3,185. Meanwhile, the Nasdaq Composite Index COMP, +0.58% was up 0.1% and an index tracking the largest 100 of that benchmark, the Nasdaq-100 NDX, +0.97% was up 0.6%. Both the Nasdaq and the Nasdaq-100 were trading in record territory. The Fed is set to produce its updated policy statement at 2 p.m. Eastern Time and Chairman of the rate-setting Federal Open Market Committee, Jerome Powell, will host a news conference at 2:30 p.m.