U.S. stock futures dipped in overnight trading Sunday after the Dow Jones Industrial Average turned in three straight weeks of losses for the first time since September 2020.

Futures on the Dow shed 114 points, or 0.3%. S&P 500 futures fell 0.3% and Nasdaq 100 futures ticked 0.2% lower.

Stocks have struggled in September, a seasonally weak month for the market.

The Dow closed Friday’s regular session 166.44 points, or 0.5%, lower at 34,584.88. The S&P 500 shed 0.9% to 4,432.99 and the Nasdaq Composite lost 0.9% to close at 15,043.97.

The S&P 500 saw its biggest trading volume Friday since July 19, more than doubling its 30-day average volume. Friday coincided with the expiration of stock options, index options, stock futures and index futures — a quarterly event known as “quadruple witching.”

All three major averages are negative for the month, but still sit less than 3% below their all-time highs.

The Federal Reserve’s highly anticipated September meeting is set to occur this week. Fed Chair Jerome Powell will hold a press conference Wednesday at the conclusion of the two-day meeting. Investors are awaiting insights about the Fed’s tapering of its easy monetary policy.

Powell has said the so-called tapering could occur this year, but investors are waiting for more specifics, particularly after mixed economic data released since Powell’s last comments.

“Factors to build a ‘wall of worry’ are present (i.e., China, supply chain issues, Fed policy, debt ceiling, infrastructure/tax bill), though markets are not too disturbed for now. Normal pullbacks and volatility are to be expected, and we would use these periods as opportunities,” Raymond James Chief Investment Officer Larry Adam said in a note.

Investors also await a number of major quarterly earnings reports this week with Adobe, FedEx, Darden Restaurants, Nike and Costco posting financial results.