(Updates with market moves at the end of the day and latest developments.)
The Dow Jones Industrial Average logged its sharpest single-day decline in four weeks in a mixed session on Wednesday, as oil prices rallied after President Donald Trump warned of additional attacks on Iran.
The Dow fell 1.1% to 52,348.4, its biggest percentage fall since June 10. The S&P 500 declined 0.3% to 7,482.7, while the Nasdaq Composite edged up 0.2% to 25,870.7. Barring energy and technology, all sectors were in the red led by materials.
West Texas Intermediate crude oil was up 5.1% at $74.01 per barrel in Wednesday late-afternoon trade, while Brent jumped 5.8% to $78.46.
During a North Atlantic Treaty Organization summit in Turkey on Wednesday, Trump said the memorandum of understanding signed with Iran last month to end the war in the Middle East was "over."
The US struck Iran on Tuesday after Tehran attacked three tankers that crossed the Strait of Hormuz. Iran's Islamic Revolutionary Guard Corps hit US military targets across Bahrain and Kuwait in retaliation to Washington's attacks, CNN reported.
Trump warned of more attacks on Iran.
"We hit them very hard last night," Trump said in Turkey. "We'll probably hit them hard again tonight."
A peace deal between the US and Iran is a key risk to watch in the second half of 2026 as energy prices may determine inflation expectations, Oxford Economics Chief Global Economist Ryan Sweet said in remarks emailed to.
"If the peace deal breaks, and it's too early to tell, it won't just raise oil prices; it would also increase pressure on (artificial intelligence) supply chains in Asia, force central banks to be hawkish, tighten financial conditions, and could shift the outcome of the US midterms," Sweet said. "The cascade runs fast."
US Treasury yields were higher, with the two-year rate increasing 4.4 basis points to 4.21% and the 10-year rate adding 4.2 basis points to 4.57%.
Federal Reserve officials held diverging views last month on the appropriate path of interest rates, minutes from the central bank's June policy meeting showed Wednesday. At that meeting, the Federal Open Market Committee unanimously decided to maintain the policy rate steady for the fourth consecutive time.
"The June minutes put the focus on an uncertain balance of risks," TD Economics said in a report. "Participants agreed on holding rates steady in June, but not on whether the next move is more likely to be up or down, making future meetings more 'live' and dependent on incoming data."
The International Monetary Fund lowered global economic growth expectations for 2026 as the impact of the Middle East war will likely counter a boost from rising artificial intelligence adoption.
In company news, Apple (AAPL) said Wednesday that Broadcom (AVGO) will produce chips to be used in the iPhone maker' products in a deal likely worth more than $30 billion. Shares of Apple rose 0.9%, among the biggest gainers on the Dow, while Broadcom advanced 4.8%.
Nvidia (NVDA) shares advanced 3.7%, the best performer on the Dow.
Alibaba Group (BABA), ByteDance, and DeepSeek could receive permission from China to purchase a limited volume of Nvidia H200 chips to offset a shortage due to increasing demand for artificial intelligence chips, The Information reported Wednesday, citing sources with knowledge of the matter.
Moderna (MRNA) slumped 7.5%, the second-worst performer on the S&P 500.
Major US biopharmaceutical companies' performance in the second half of the year is likely to be driven largely by fundamentals as the focus shifts away from economic factors, Morgan Stanley said in a note.
Gold shed 1.7% to $4,087.30 per troy ounce, while silver lost 4.2% to $58.75 per ounce.
