Oil prices leaped on worries that war with Iran could clog the flow of crude, while U.S. stocks swung from sharp losses to small gains.

The S&P 500 fell as much as 1.2% Monday, and cruise lines and airlines led the way lower on worries about higher fuel bills. But U.S. stocks quickly erased those losses, in part because past military conflicts haven’t usually created sustained drops for the market. The index finished with a gain of less than 0.1%.

The Dow fell 0.1%, and the Nasdaq composite rose 0.4%. Oil and defense stocks rallied. Treasury yields rose with worries about inflation.

On Monday:

The S&P 500 rose 2.74 points, or less than 0.1%, to 6,881.62.

The Dow Jones Industrial Average fell 73.14 points, or 0.1%, to 48,904.78.

The Nasdaq composite rose 80.65 points, or 0.4%, to 22,748.86.

The Russell 2000 index of smaller companies rose 23.58 points, or 0.9% to 2,655.94.

For the year:

The S&P 500 is up 36.12 points, or 0.5%.

The Dow is up 841.49 points, or 1.8%.

The Nasdaq is down 493.13 points, or 2.1%.

The Russell 2000 is up 174.04 points, or 7%.