Wall Street opened mixed on Monday, pressured by investor fears the Federal Reserve’s aggressive monetary tightening will hurt the U.S. economy and a decline in Pfizer after its decision to drop the development of a weight loss drug.

The Dow Jones Industrial Average (.DJI) rose 3.36 points, or 0.01 percent, at the open to 33,730.79. The S&P 500 (.SPX) opened lower by 3.49 points, or 0.08 percent, at 4,344.84, while the Nasdaq Composite (.IXIC) dropped 23.77 points, or 0.18 percent, to 13,468.75 at the opening bell.