(Updates with index/price moves and company/geopolitical news from the first paragraph.)

US equity indexes traded mixed amid growing investor concerns over circular corporate investments and as crude oil prices plunged after a pause in Iran strikes entered its third day.

The Dow Jones Industrial Average climbed 0.6% to 52,249.1, and the S&P 500 rose 0.1% to 7,420.2 after midday Monday. The Nasdaq Composite was little changed at 24,972.6.

Energy and technology led decliners while communication services, consumer staples, and consumer discretionary topped the gainers.

Nvidia (NVDA) has agreed to expand its partnership with South Korean conglomerate SK Group through an artificial intelligence infrastructure initiative valued at more than $500 billion. The deal announced Saturday includes a long-term partnership between Nvidia and SK Hynix (SKHY) that will provide the US technology giant a stable supply of next-generation AI memory. Nvidia's shares dropped 4.5%, one of the bottom five in the Dow. The SK Hynix stock plummeted 8%.

VanEck Semiconductor ETF (SMH), with net assets of $77.2 billion, slumped 4.4%.

Meanwhile, the US paused military attacks against Iran over the weekend, while Tehran also refrained from retaliatory action, according to a Commerzbank note. Meanwhile, Oman and Iran continued discussions on a transit arrangement for the Strait of Hormuz, with diplomats describing the negotiations as "moving in the right direction." Iranian officials likewise characterized the talks as "constructive."

The front-month US West Texas Intermediate sank 6.3% to $83.65 a barrel, and global benchmark North Sea Brent plunged 6.9% to $90.09 a barrel.