A closely watched gauge of future economic activity rose in November, breaking a nearly three-year streak of declines, as the U.S. economy responded to President-elect Donald J. Trump’s victory.

The Conference Board’s Leading Economic Index, released on Thursday, increased 0.3 percent last month after slipping 0.4 percent in October. The rebound surpassed economists’ forecasts, which had anticipated a further decline of 0.1 percent, according to a survey by Econoday.

The index—which aggregates data from indicators including stock prices, building permits, and initial claims for unemployment insurance—was buoyed by a rally in equities and a resurgence in building permits. The labor market also contributed, with gains in average hours worked in manufacturing and fewer applications for unemployment benefits.

“Overall, the rise in the LEI is a positive sign for future economic activity in the U.S.,” said Justyna Zabinska-La Monica, a senior manager at The Conference Board.

November’s uptick comes after Mr. Trump’s unexpected election victory on Nov. 8, which has spurred optimism across sectors. Analysts pointed to the president-elect’s promises of tax cuts, deregulation, expansive energy policy, stronger trade deals backed by tariffs, and infrastructure investment as fueling a surge in business confidence.

With the latest increase, the LEI no longer signals an imminent recession, according to The Conference Board. The index typically predicts shifts in the economic cycle about seven months in advance.