The S&P 500 and the Nasdaq notched record high closes Thursday as robust results from Google parent Alphabet fueled optimism about other heavyweight artificial intelligence stocks, while Tesla slumped after the electric vehicle maker's results disappointed investors.

Alphabet rose as the search giant's results boosted confidence that heavy investment in a race to dominate AI technology is paying off.

Shares of Microsoft, Nvidia and Amazon also climbed.

The U.S.-Japan trade deal and recent signs of progress in talks with the European Union also fueled Wall Street's gains.

"Investors are feeling optimistic about trade negotiations, about the economy, the trend in inflation, as well as the better-than-expected Q2 earnings reports," said Sam Stovall, chief investment strategist at CFRA Research.

Tesla tumbled after CEO Elon Musk warned of a "few rough quarters" as the U.S. government cuts support for electric vehicle makers. The stock has fallen around 25% so far in 2025.

UnitedHealth fell after the insurer revealed it was cooperating with a Department of Justice probe into its Medicare practices, following reports of both criminal and civil investigations.

IBM dropped after its second-quarter results fell flat with investors, hampered by disappointing sales in its core software division.

Honeywell fell despite topping Wall Street's expectations and raising its annual outlook.

According to preliminary data, the S&P 500 gained 5.53 points, or 0.08%, to end at 6,363.87 points, while the Nasdaq Composite gained 38.85 points, or 0.19%, to 21,057.96. The Dow Jones Industrial Average fell 312.08 points, or 0.69%, to 44,698.21.

American Airlines tumbled after the carrier forecast a big third-quarter loss, hurt by sluggish domestic travel demand.

U.S. President Donald Trump's global trade war has created the biggest uncertainty for the airline industry since the COVID-19 pandemic.

Markets were also monitoring Trump's planned visit to the Federal Reserve's headquarters on Thursday, following months of the president criticizing Fed Chair Jerome Powell for interest rates Trump views as too high.

With the Fed widely expected to hold rates steady at next week's meeting, traders see a 60% chance of a September rate cut, according to CME's FedWatch tool.

A U.S. Labor Department report showed jobless claims last week fell to 217,000 - well below estimates - signaling continued resilience in the job market.

U.S. business activity gained momentum in July, but companies hiked prices on goods and services, fueling economists’ predictions of faster inflation in the months ahead, largely driven by rising import tariffs.