NEW YORK>> Hour-to-hour swings for oil prices keep jerking financial markets around, and U.S. stocks wavered Thursday following the latest reversal.

The S&P 500 rose 0.2% and inched closer to its all-time high set last week. The Dow Jones Industrial Average added 276 points, or 0.6%, and the Nasdaq composite climbed 0.1%.

All three indexes erased early drops and gained strength following the latest U-turn for oil prices. Brent crude oil briefly got above $109 per barrel in the morning, threatening to worsen the world’s already high inflation, before quickly erasing all its gains in midday trading and falling 2.3% to settle at $102.58.

Oil prices are yo-yoing because of uncertainty about how long the war with Iran will keep the Strait of Hormuz shut. The closure has prevented oil tankers from exiting the Persian Gulf to deliver crude to customers worldwide, driving up oil’s price.

As oil prices eased Thursday, so did pressure on Wall Street that’s been building from the bond market.

Yields had climbed so high that they threatened to slow economies worldwide and undercut prices for stocks, bitcoin and all kinds of other investments. They’ve already forced the average long-term U.S. mortgage rate to its most expensive level since last summer, and they could curtail companies’ borrowing.

The yield on the 10-year Treasury briefly got near 4.63% in the morning before falling back to 4.55% following the midday turnaround for oil prices. That’s down from 4.57% late Wednesday and from 4.67% the day before.

Some of the biggest beneficiaries of lower yields can be the smallest companies, many of which need to borrow money to grow. The Russell 2000 index of the smallest U.S. stocks climbed 0.9%, far more than the rest of the market.

All told, the S&P 500 rose 12.75 points to 7,445.72. The Dow Jones Industrial Average climbed 276.31 points to 50,285.66, and the Nasdaq composite gained 22.74 to 26,293.10.

A preliminary report on U.S. business activity suggested that companies are also feeling the bite of higher inflation.

A flash survey from S&P Global said growth in activity for U.S. services businesses unexpectedly slowed a tad, though growth was better than forecast for U.S manufacturers.