* S&P 500, Nasdaq end lower
* Oil prices gain as Iran worries continue
* Longer-dated U.S. Treasury yields off recent highs (Updates with oil settlement, S&P 500 and Nasdaq closing lower)
NEW YORK/LONDON, May 18 (Reuters) - Major stock indexes mostly eased as technology shares fell on Monday, while oil prices climbed following continued worries over supply disruption from the Iran war.
Longer-dated U.S. Treasury yields were nearly flat after climbing to their highest level in over a year in overnight trading. Sovereign bond yields have risen sharply recently as investors worry the war in Iran that began in late February may bring a lasting inflationary shock.
President Donald Trump posted on social media on Monday that he was holding off on a planned military attack on Iran scheduled for Tuesday, while efforts continue to reach a deal. He added that the United States was ready to resume attacking if one is not reached.
U.S. crude rose $3.24 to settle at $108.66 a barrel, while Brent crude gained $2.84 to $112.10. Investors are also focused on the tech sector's recent sharp gains and are bracing for results from Nvidia this week.
Technology, down 1%, led sector declines in the S&P 500, while an index of semiconductors was down 2.5%. Energy led sector gainers and was last up 1.8%.
Trump's recent trip to China "left a lot of open questions about the future of Taiwan and whether or not the United States would be there to protect it," said Oliver Pursche, senior vice president, advisor for Wealthspire Advisors in Westport, Connecticut.
"Given Taiwan's significance to the chip market, that partially explains the selloff we're seeing in that sector today," he said, adding that investors are also taking profits. Trump's first visit to Beijing since 2017 ended on Friday with no major breakthroughs on trade or tangible help from Beijing to end the U.S.-Israeli war on Iran.
The Dow Jones Industrial Average rose 159.95 points, or 0.32%, to 49,686.12, the S&P 500 fell 5.45 points, or 0.07%, to 7,403.05 and the Nasdaq Composite fell 134.41 points, or 0.51%, to 26,090.73.
MSCI's gauge of stocks across the globe fell 0.24 points, or 0.02%, to 1,098.76. The pan-European STOXX 600 index rose 0.54%.
Rising yields push up borrowing costs and mean a higher discount for future company earnings, challenging stock valuations.
The yield on the benchmark 10-year Treasury note climbed to 4.659% in overnight trading, its highest level since February 2025. It has since retraced its gains and was last flat on the day at 4.591%.
Earlier, Japan's 10-year yield hit a peak not seen since 1996 as the government proposed to issue fresh debt to fund a planned extra budget to cushion the economic blow from the Iran war. Germany's 10-year bond yield rose to a level not seen in 15 years.
AI, RETAIL EARNINGS TO TEST STOCKS' RECENT RALLY
The artificial intelligence trade will be tested by earnings from Nvidia that are due on Wednesday, with expectations sky-high for the world's most valuable company.
Nvidia shares are up sharply since a March low, while the Philadelphia SE semiconductor index has also surged amid demand for chips as tech companies spend massively to build AI-related infrastructure.
Also due this week are results from a host of retailers, including Walmart, which will provide an insight into how consumers are faring with high energy prices. The dollar slipped against most major currencies as U.S. Treasury yields were off recent high levels.
The dollar index, which measures the greenback against a basket of currencies including the yen and the euro, fell 0.33% to 99.03.
Spot gold rose 0.31% to $4,552.19 an ounce.
Commodities Forex Market News

* U.S. Treasury yields hit one-year peaks; JGB yields scale record highs


* U.S. stock indexes mostly down slightly


(Alliance News) - The FTSE 100 closed higher on Monday, recouping most of Friday's hefty falls, amid a calmer bond market and as Iran responded to the...