Wall Street's main indexes dipped on Monday as investors paused to take stock of a stellar month ahead of crucial economic reports this week.
Nine of the 11 major S&P 500 sectors were trading lower, with energy the biggest decliner in early trading. Oil majors including Exxon Mobil, Chevron and ConocoPhillips fell between 1.8 percent and 2.5 percent, tracking a decline in crude prices.
IHS Markit topped gains on the benchmark S&P 500 after data giant S&P Global agreed to buy the financial information provider in a $44 billion deal, which will be the biggest corporate acquisition of 2020.
Analysts said the month-end rebalancing of portfolios also played into on Monday's weakness as investors cash in on gains after a strong month marked by updates of COVID-19 vaccines making headway and hopes of a swift economic rebound next year.
A rotation into sectors deemed to provide better returns coming out of a recession such as energy, industrials and financials have powered the S&P 500 for its best November ever. The Dow is on track for its biggest monthly gain since 1987.
"Markets can, and have, looked through the strain that the virus' resurgence is putting on the economy through to a vaccine where the population can start to get back to normal," said Keith Buchanan, senior portfolio manager at GLOBALT in Atlanta.
"The question is if the market's forward looking mechanism is strong enough to outweigh what seems to be an unrelenting virus and the challenges it presents to the day-to-day activities of the economy."
At 10:13 a.m. ET, the Dow Jones Industrial Average fell 291.37 points, or 0.93 percent to 29,619.00 and the S&P 500 lost 17.63 points, or 0.48 percent to 3,622.08. The Nasdaq Composite lost 25.15 points, or 0.22 percent to 12,182.56 after hitting an all-time early in the session.
Technology and healthcare were the only two sectors trading higher.
US Health Secretary Alex Azar on Monday said the first two vaccines against the novel coronavirus could be available to Americans before Christmas.
Moderna unveiled plans to apply for US and European emergency authorization for its COVID-19 vaccine after full results from a late-stage study showed it was 94.1 percent effective, sending its shares up 16 percent.
After an explosion in infections and business restrictions this month that undermined the US labor market recovery, focus will be on the monthly employment report and the Fed's Beige Book, as well as an address by Fed Chair Jerome Powell before the Senate Banking Committee.
Macy's Inc and Kohl's Corp slipped about 4 percent each as masked shoppers turned up in smaller numbers at major US retailers on Black Friday as early online deals and concerns about a spike in COVID-19 cases dulled enthusiasm for mall trips.
Declining issues outnumbered advancers ones by 2-to-1 ratio on the NYSE and on Nasdaq a 0.6-to-1 ratio favored decliners.
The S&P 500 posted eight new 52-week highs and no new lows; the Nasdaq Composite recorded 222 new highs and five new lows.