Stocks dipped on Friday as investors remain cautious due to a resurgent Covid virus, a Federal Reserve meeting next week and a historical tendency for September to be a weak month for equities.

The Dow Jones Industrial Average lost about 140 points or 0.55%, dragged down by a 3% drop in Dow Inc. The S&P 500 shed 0.9% and the Nasdaq Composite lost more than 1%.

Mega-cap technology stocks were mostly in the red, with social media giant Facebook dropping 2.5%. Apple and Microsoft also lost 1%.

The Food and Drug Administration advisory committee on Friday rejected a plan to administer booster shots of Pfizer and BioNTech‘s Covid-19 vaccine to the general public. Pfizer fell 1.2% and BioNTech dropped 4.3%. Moderna lost 5%.

History is not on the market’s side with the S&P 500 averaging a 0.4% decline for September, the worst of any month, according to the Stock Trader’s Almanac. Friday in particular begins a historically weak period for stocks as those September losses typically come in the back half of the month.

Some of the volatility that comes during September is often surrounding so-called quadruple witching, which occurs at the close Friday. This is the expiration of stock index futures, stock index options, stock options, and single-stock futures.

“We expect volatility to increase over the next month driven by a seasonal pickup in investor uncertainty, continued virus uncertainty, and significant monetary and fiscal policy catalysts,” wrote John Marshall, head of derivatives research for Goldman Sachs, in a note Friday. Marshall cited data showing S&P 500 volatility typically increased by 27% from August to October.

Still, stocks are heading into Friday with losses for the week. The Dow is down 0.17% and the S&P 500 is down 0.56% since Monday. The Nasdaq Composite has dropped 0.5% this week.

For the month, stocks are in the red. The Dow is down 2.25% in September. The S&P 500 is off by 2% this month but still just 2.5% from its all-time high. The Nasdaq has lost 1.5% this month.

The Federal Reserve meets for two days next week and on Wednesday is expected to give further clues as to when it may start to slow its $120 billion in monthly bond purchases that have supported the recovery, but also perhaps aided in a jump in inflation.

The U.S. 10-year Treasury hopped 4 basis points to 1.37% on Friday.

Fed Chief Jerome Powell has said the so-called tapering could occur this year, but investors are waiting for more specifics. Some investors fear a decline in asset prices as the central bank begins to take away its easy policies.

Shares of Invesco jumped 5% after the Wall Street Journal reported the money manager is in talks to combine with State Street’s asset-management business. Invesco manages about $1.5 trillion.