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.

The Dow futures lost 65 points or 0.2%. S&P 500 futures fell 0.2% and Nasdaq 100 futures ticked 0.2% lower.

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

Friday’s session ended with the Dow closing at 34,584.88, 166.44 point (or 0.5%) lower. 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.”

Although all three main averages have fallen to a negative level for the month they are less than 3 percent below their historic highs.

It is expected that the Federal Reserve’s September meeting will be held this week. The two-day meeting will end with Fed Chair Jerome Powell holding a press conference Wednesday. Investors await information about Fed’s planned tapering of its easy-money policy.

Powell stated that tapering may occur this year. Investors are still waiting to hear more, particularly with mixed economic data since Powell’s last comment.

Although markets don’t seem to be too worried for the moment, there are factors that could cause a “wall of worry” (e.g., China supply chain issues and Fed policy as well as debt ceiling, infrastructure, tax bill, and Fed policy), but they are still able to create a wall. “Normal pullbacks, volatility are to expected,” Raymond James Chief Investor Officer Larry Adam wrote in a note.

Investors will also be waiting for major quarterly earnings reports, including those from Adobe, FedEx (Darden Restaurants), Nike, Costco and Darden Restaurants.