U.S. stock markets closed with mixed results on Wednesday, as the Dow Jones Industrial Average surged to a new all-time high. The S&P 500 index snapped a four-day winning streak.

The Dow climbed 263.24 points, or 0.49%, to finish at 54,349.12. In contrast, the Nasdaq Composite fell 221.55 points, or 0.83%, to 26,363.44, and the S&P 500 slipped 12.97 points, or 0.17%, to 7,723.55. Earlier in the morning, the S&P 500 had briefly touched a record intraday high.

Buoyed by strong earnings reports and a rally in shares of Nvidia Corp (NASDAQ: NVDA), the Dow achieved its fifth consecutive day of gains and a new closing record. Nvidia shares closed 3.4% higher after Elon Musk stated that SpaceX will exclusively use Nvidia processors when building its future artificial intelligence computing infrastructure. During a SpaceX earnings call, Musk remarked that Nvidia has the "best AI computers," adding, "we only use Nvidia."

However, shares of SpaceX (NASDAQ: SPCE) dropped 13.6% following the release of its first quarterly report since going public in June. The company reported a six-fold surge in second-quarter capital expenditure to $18.4 billion, which exceeded analyst expectations and was largely driven by spending on AI.

Chip giant Advanced Micro Devices Inc (NASDAQ: AMD) and "Magnificent Seven" member Alphabet Inc (NASDAQ: GOOGL) underperformed. AMD fell over 7% after reporting adjusted earnings per share that only slightly surpassed Wall Street estimates. Alphabet declined 4% after announcing a restructuring of its AI division, with chief scientist Jeff Dean leaving the company after 27 years.

The previous trading session was strong, with the S&P 500 closing above the 7,700 mark for the first time and the Dow also hitting a record close. "Animal spirits seem to have really returned forcefully," said Ross Mayfield, an investment strategist at Baird, noting that the magnitude of market moves over the past few days has been "historically quite rare." On Tuesday, the three major indexes posted their best four-day performance since April 2025.

Market sentiment this week has also been supported by expectations of a potential reopening agreement for the Strait of Hormuz in the Middle East. Oil prices remained steady on Wednesday, following Treasury Secretary Scott Bessent's comments on Tuesday that the U.S. and Iran might be close to a deal to reopen the Strait. West Texas Intermediate crude for September delivery slipped slightly to around $74 per barrel. The international benchmark, Brent crude for October delivery, traded at approximately $79 per barrel.