The S&P 500 nudged to a record high on Thursday, shrugging off weak tech earnings to close above its level in October, a high point before worries over corporate spending on artificial intelligence dragged the market lower.

The index rose just 0.2 percent on Thursday, after recovering from losses earlier in the day that were attributed to worries over Oracle’s latest earnings and the company’s outlay on A.I. Worries over the bet on the transformative potential of A.I have intensified in recent weeks.

But buyers emerged in the afternoon, adding to gains from Wednesday when the Federal Reserve cut interest rates by a quarter of a percentage point and Jerome H. Powell, the central bank’s chair, stressed the importance of protecting against further weakness in the economy, which could mean more interest rate cuts to come.

The Russell 2000 index of smaller companies, seen by investors as sensitive to changes in interest rate expectations, has risen more sharply this week. It notched a new high on Wednesday and rose further into record territory on Thursday.

Fed officials on Wednesday barely shifted their outlook for interest rate cuts, despite lifting their forecast for the economy next year. Despite flagging risks to the outlook, equity investors appeared buoyed in afternoon trading.

“Powell got out his three wood and hit it right down the middle,” said Ryan Detrick, chief market strategist at Carson Group, on Wednesday. “The market got the cut it wanted and although a January cut isn’t the base case, by no means did they put cold water on that potential move.”

Investors are betting the next rate cut will come after Mr. Powell has stepped down as chair, in May, with a total of two quarter-point cuts priced into interest rate markets through December next year.

That outlook is clouded by uncertainty over who will succeed Mr. Powell as chair.

“Yes, Powell is with us well into next year,” said Peter Tchir at Academy Securities, but he expects the Trump administration, “to step up the rhetoric for rate cuts once we start the new year.”

After the close of trading, Broadcom, another big tech company that has dived into A.I., reported positive earnings, lifting its stock price in after-hours trading and adding a tailwind to the S&P 500 heading into Friday.