Falling oil prices help calm worries about inflation, and Wall Street rallies

NEW YORK (AP) — Oil prices are easing on Monday and helping to calm Wall Street’s worries that inflation could get even worse. That has U.S. stock indexes rallying, though sharp swings are continuing to roil underneath the surface.

The S&P 500 rose 1.5% following its wild July, where it swung up and down as oil prices shot higher because of the war with Iran and other worries. The Dow Jones Industrial Average was up 591 points, or 1.1%, as of 1:57 p.m. Eastern time, and the Nasdaq composite was 2.2% higher.

Stocks got a lift as the price for a barrel of Brent crude sank 5% to $83.49. It dropped after President Donald Trump said over the weekend that he decided to hold off on new strikes against Iran at the urging of allies in the region.

Brent's price careened between $72 and $102 last month as worries rose and fell about when the war with Iran would allow oil tankers to freely exit the Persian Gulf again to deliver crude to customers worldwide. The latest acquiescence by Trump on Iran helped to ease worries about the global flow of crude, and Treasury yields correspondingly fell in the bond market.

The yield on the 10-year Treasury sank to 4.69% from 4.75% late Friday. It, though, remains well above its 3.97% level from before the war with Iran.

Higher yields threaten to undercut prices for stocks and other investments, while slowing the economy by making borrowing more expensive for U.S. households and businesses. The average long-term U.S. mortgage rate has already leaped to its highest level in a year.

Monday's ease in oil prices helped airlines and other companies with big fuel bills lead the market. United Airlines flew 5.2% higher, while American Airlines climbed 4.2%. Norwegian Cruise Line Holdings steamed 3.9% higher.

Tyson Foods rose 2% after the meat company reported a slightly stronger profit for the spring than analysts expected. CEO Donnie King said strength is continuing in the company's chicken business and its prepared foods, which include brands like Jimmy Dean and Hillshire Farm.

It joined a lengthening list of big U.S. companies to deliver a bigger profit for the spring than analysts expected. That's imperative for Wall Street because stock prices tend to follow the path of corporate earnings over the long term, and worries were rising that stock prices may have already shot too high.

Companies in the S&P 500 are on track to deliver earnings per share for the spring that are 47% higher than a year before, according to FactSet, with more than half of the companies having already reported. If that ends up being the case, it would be the strongest growth since the spring of 2021, when the economy was roaring out of the COVID pandemic.

Also offering encouragement for profits was a report on Monday showing that growth for U.S. manufacturing accelerated to its strongest level since 2022.

Keeping Wall Street unsettled, though, were swings for stocks of companies that make computer chips. They've been veering up and down for weeks on worries about whether their surging revenues because of the artificial-intelligence boom are sustainable.

If AI ends up producing less profit and productivity than hoped, Big Tech companies could curtail their spending sprees on data centers that have helped chip stocks soar to tremendous heights.

Micron Technology went from a drop of 6.4% to a gain of 0.7% during Monday's first 90 minutes of trading, for example. It's still up roughly 190% for the year so far.

The manic swings for AI stocks have been most dramatic in South Korea, where the Kospi index is dominated by just two tech titans, Samsung Electronics and SK Hynix.

Seoul’s Kospi fell 5.1% Monday, coming off Friday's 17.9% surge that was its best day in history.

In neighboring Japan, Tokyo’s Nikkei 225 fell 0.9% after the United States and Japan confirmed they had moved together to to prop up the value of the Japanese yen against the dollar. A stronger yen would help to limit inflation in Japan, but it could also potentially hurt Japan’s exporters.

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AP Writers Matt Ott, Elaine Kurtenbach, Mayuko Ono and Mari Yamaguchi contributed to this report.