NEW YORK — U.S. stocks sank again Wednesday, cementing February as the worst month for the market in two years.

Not only was the month’s loss sharp, at 3.9 percent for the Standard & Poor’s 500 index, it also was the first in a long time. S&P 500 index funds snapped a record-setting run in which they had made money for 15 straight months, including dividends.

Some of Wednesday’s drop was tied to a slide in the price of oil, which caused energy stocks to suffer the sharpest market losses Wednesday. The S&P 500 fell 30.45 points, or 1.1 percent, to 2,713.83, while the Dow Jones industrial average sank 380.83 points, or 1.5 percent, to 25,029.20 and the Nasdaq composite dropped 57.35, or 0.8 percent, to 7,273.01.

The dominant fear for the month was the threat of higher inflation and interest rates. Concerns got so high that the S&P 500 spiraled down 10 percent in just nine days at one point, before trimming some of its losses. The index had five losses of 1 percent or more in February, more than it did in all of last year.

INTEREST RATES, HIGH UNCERTAINTY

Expect even more swings in coming weeks and months, said Brian Peery, portfolio manager at Hennessy Funds. Investors are trying to figure out how many times the Federal Reserve will raise interest rates this year in the face of a growing economy. Uncertainty is high given that markets are waiting to see how much Washington’s recently passed tax cuts will push companies to spend on equipment and wages.

“We were without volatility for so long, but what’s in motion tends to stay in motion,” Peery said. “It’s been a pretty tumultuous month.”

The tumult started just as the month began, when a government report showed a jump in workers’ wages that surprised economists. That triggered worries that higher inflation may be on the way.

The dizzying result marked a turnaround from the market’s blistering start to the year, when stocks jumped on expectations that corporate profits would keep rising and the global economy would keep strengthening.

THE BIGGEST WINNERS AND LOSERS

On Wednesday, the yield on the 10-year Treasury fell to 2.86 percent from 2.90 percent late Tuesday.

Among the biggest losers Wednesday in the S&P 500 was Lowe’s, which reported weaker profit for the last quarter than analysts expected. The home-improvement retailer’s stock dropped $6.20, or 6.5 percent, to $89.59.

Energy stocks in the S&P 500 lost 2.3 percent, the sharpest decline among the 11 sectors that make up the index. They were hurt by a sharp drop in the price of oil after a government report showed that the amount of oil in U.S. inventories rose more than analysts expected last week.

Benchmark U.S. crude lost $1.37 to settle at $61.64 per barrel. Brent crude, the international standard, fell 85 cents to $65.78 per barrel.

On the winning side was Booking Holdings, the company formerly known as Priceline. It jumped $129.03, or 6.8 percent, to $2,034.04 after it reported a bigger profit for the latest quarter than analysts expected, aided by stronger travel bookings.