Most U.S. stocks are rising on Thursday, but a drop for Oracle is holding Wall Street back as investors question whether its big spending on artificial-intelligence technology will pay off.

The S&P 500 fell 0.4% in early trading and pulled a bit further from its all-time high, which was set in October. The Dow Jones Industrial Average was up 233 points, or 0.5%, as of 9:35 a.m. Eastern time, and the Nasdaq composite was 0.7% lower.

Oracle was one of the heaviest weights on the market and sank 14.5% even though it reported a better profit for the latest quarter than analysts expected. Its 14% growth in revenue came up just short of expectations.

Doubts also remain about whether all the spending that Oracle is doing on AI technology will produce the payoff of increased profits and productivity that proponents are promising. Analysts said they were surprised by how much Oracle may spend on AI investments this fiscal year, and questions continue about how the company will pay for it.

Such doubts are weighing on the AI industry broadly, even as many billions of dollars continue to flow in. They had helped drag the broad U.S. stock market through some sharp and scary swings last month.