The S&P 500 was steady on Wednesday, with the average still flat for the month of September, as investors reassess the economic growth outlook following a smooth ride in the market so far this year.

The Dow Jones Industrial Average dipped about 80 points. The S&P 500 traded around the flat line. The Nasdaq Composite fell slightly after closing at a record on Tuesday.

Many investors are bracing for volatility in September, one of the seasonally weakest months of the year. Price swings could make a comeback, especially with the S&P 500 up about 20% this year without a single 5% pullback.

“We see a bumpy September-October as the final stages of a mid-cycle transition play out,” Morgan Stanley chief cross-asset strategist Andrew Sheets said in a note. “The next two months carry an outsized risk to growth, policy and the legislative agenda.”

The S&P 500 fell 0.3% on Tuesday in relatively thin trading following the Labor Day weekend. The blue-chip Dow dropped 260 points, weighed down by 3M and Honeywell, while the tech-heavy Nasdaq Composite rose less than 0.1% to eke out a record close.

On Wednesday, the Labor Department will release its closely watched Job Openings and Labor Turnover Survey. Meanwhile, the Federal Reserve is set to publish its periodic “Beige Book” survey of activity across its 12 districts.

One of the catalysts for a sell-off could be the Federal Reserve and the potential for it to pull back an unprecedented monetary stimulus to support the economy throughout the pandemic. Fed Chairman Jerome Powell has indicated that the central bank is likely to begin withdrawing some of its easy-money policies before year-end, though he still sees interest rate hikes in the distance.

Still, the outlook for the liftoff is clouded by the coronavirus variant and the latest jobs report, which showed a big disappointment.

“Stocks have posted much stronger than average gains, with much shallower than average pullbacks,” Keith Lerner, chief market strategist at Truist, said in a note. “It would be perfectly normal to see at least one gut check before year end.”