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

US equity indexes traded mixed amid a sharp sell-off in communication services and reports that Iran and Oman have agreed on a proposed shipping route through the Strait of Hormuz, the chokepoint for about a fifth of global oil and natural gas flows.

The Nasdaq Composite fell 0.6% to 26,444.8, and the S&P 500 slipped 0.1% to 7,727.6 after midday Wednesday. The Dow Jones Industrial Average rose 0.8% to 54,511.2. Both the S&P 500 and the Dow scaled new peaks for a second straight day earlier in the session.

Communication services, energy and utilities led decliners. Materials and healthcare topped gainers.

Iran said it has reached a deal with Oman on a proposed shipping route through the Strait of Hormuz, a potential step toward a reopening of the waterway for energy supplies, Bloomberg reported Wednesday.

A joint statement from the two countries is in the final drafting stage, Iran's foreign ministry spokesman Esmail Baghaei was cited as saying Wednesday, Bloomberg reported. Talks between Iran and Oman are "forward-moving," and an agreement would be struck "if certain third parties do not obstruct this process," Baghaei was cited as saying, according to the report.

The front-month US West Texas Intermediate crude oil slipped 0.4% to $75.48 a barrel, and global benchmark North Sea Brent edged up 0.1% to $79.44 a barrel.

SpaceX (SPCX) reported Q2 capital expenditures of $18.37 billion, up from $2.83 billion a year ago, taking the shine off a narrower-than-expected loss and above-consensus revenue growth. Shares slumped 8%, among the worst performers on the Nasdaq.

Shares of Advanced Micro Devices (AMD) dropped 5.5%, one of the steepest decliners on the Nasdaq, after analysts, in a post-earnings conference call late Tuesday, raised questions about the chipmaker's gross margin trajectory. The company reported fiscal Q2 adjusted earnings and revenue above market expectations, and Q3 sales guidance beat consensus.