The Dow ended lower and the S&P 500 finished close to flat Wednesday after the Federal Reserve cut interest rates but Fed Chair Jerome Powell said another rate cut in December is far from assured.

The Nasdaq was higher, boosted by Nvidia, which during the session rose past $5 trillion in market valuation.

After Powell spoke, traders pared bets on a December rate cut, now giving it a 71% chance, down from 90%. In earlier trading, stocks rose and then added to gains after the Fed cut interest rates by a quarter of a percentage point, as expected, and said it will restart limited purchases of Treasury securities.

Fed policymakers also noted the limits in their decision-making process due to the U.S. federal government shutdown. The Fed lowered the overnight benchmark rate to a target range of 3.75% to 4.00%, the second time the U.S. central bank eased this year.

"Chairman Powell indicated that another rate cut is not a foregone conclusion," said Oliver Pursche, senior vice president and advisor for Wealthspire Advisors in Westport, Connecticut.

"But no rate cut is ever a foregone conclusion. So, to me, that is not an inappropriate comment. The (Fed) is data dependent."

During the session, Nvidia became the first company to crack $5 trillion in market valuation. It has risen more than 50% this year, leading the AI rally on Wall Street.

According to preliminary data, the S&P 500 gained 0.50 points, or 0.01%, to end at 6,891.39 points, while the Nasdaq Composite gained 130.98 points, or 0.58%, to 23,965.74. The Dow Jones Industrial Average fell 62.39 points, or 0.13%, to 47,643.98.

Investors are anxiously awaiting results from several megacaps this week, with Meta Platforms, Microsoft and Alphabet all due after the bell.

Earnings have been mostly stronger than expected this reporting period. Of the 222 companies in the S&P 500 that have reported so far, about 85% have posted earnings above analyst expectations, according to data compiled by LSEG as of Wednesday.

Caterpillar shares jumped on a third-quarter profit beat.