U.S. stocks slid on Monday but still delivered a record-breaking November marked by major developments on the political, economic and coronavirus fronts.

The Dow Jones industrial average gave up nearly 270 points, or 0.9 percent, by market close, but nonetheless bagged its best monthly performance since 1987. The S&P 500 slipped 16 points, nearly 0.5 percent, to close up more than 11 percent for the month, its best November since 1928. The tech-heavy Nasdaq gave up just a few points, slipping 0.06 percent.

Markets have been on the upswing since news outlets declared Democrat Joe Biden the winner of the Nov. 3 presidential election, creating political clarity even as President Trump pressed baseless claims of widespread voter fraud and refused to concede. Then came several announcements indicating the effectiveness of multiple coronavirus vaccine candidates. The recent formal launch of the White House transition lifted Wall Street’s optimism further, notching double-digit growth and cementing November’s broad-based rally as one of the best performances in more than 90 years.

The Dow, which last week surpassed 30,000 for the first time, climbed 12 percent in November. Analysts are encouraged by the makeup of the rally, which has broadened beyond the giant technology companies that fueled much of Wall Street’s comeback in the summer months.

“Industrials and value names have started to climb this year as the market strength continued to broaden in the month of November,” said Michael Farr, president of Farr, Miller & Washington.

Other sectors also powered the gains, as are smaller companies — another upbeat economic indicator. The Russell 2000 index, comprising small-cap stocks, surged more than 16.2 percent in November, marking the biggest monthly gain since the index began tracking its companies in 1984.

Wall Street also cheered Biden’s early Cabinet picks. Perhaps chief among those was the selection of Janet L. Yellen to head the Treasury Department. Yellen led the Federal Reserve from 2014 to 2018, overlapping the Obama and Trump administrations. During the pandemic, she has emerged as a leading voice urging robust spending from Congress to avoid further economic damage. She has also praised other governments that have taken a more aggressive approach to containing the virus.

On Nov. 23, nearly three weeks after the election, the head of the General Services Administration formally notified Biden that the transfer of power could begin. The crucial bureaucratic step — which allows the incoming administration to access public funds, participate in security briefings and access the expertise of the federal bureaucracy — was seen as a stabilizing signal to investors even as Trump refused to acknowledge his defeat.

“November’s rally built on three very promising vaccines for covid-19, greater post-election certainty that includes market-friendly Cabinet nominations, and a forthcoming peaceful transition of power,” Farr said. But there are still major concerns for the weeks and months ahead, he added: An unrelenting pandemic, households in desperate need of government aid, volatile political dynamics in the Middle East, and protracted trade tensions with China.

In November, the United States was recording more new coronavirus cases than ever — more than 100,000 per day — and many states reported record-high caseloads and hospitalizations. More than 13.4 million Americans have fallen ill and 266,000 have died since the virus took hold in spring.

Biden’s win means the country will probably take a more traditional approach to trade policy, which will in turn provide more clarity for investors, said Kristina Hooper, the chief global market strategist at Invesco. “The good news is that we now have a lot of visibility and clarity on 2021, and that has been the main driver of the November rally,” she said, describing the wave of vaccine announcements as a “game changer.”

The resurgence of Wall Street dealmaking is another sign of growing business confidence, even as the virus continues to spread.

On Monday, S&P Global announced that it will merge with IHS Markit in a $44 billion all-stock deal, in the biggest corporate tie-up of 2020, creating a financial data colossus. During the third quarter, mergers and acquisitions around the world tallied more than $1 trillion worth of transactions, according to Refinitiv data, after deals plummeted earlier this year because of the pandemic.

Nicole Tanenbaum, partner and chief investment strategist at Chequers Financial Management, said a recovery is still far in the distance as virus infections surge. But “investors have continued to keep an eye toward the long-term economic implications an effective vaccine will ultimately bring to a post-pandemic world.”