U.S. stocks fell slightly on Thursday as investors kept an eye on the artificial intelligence trade as names in the space reach eye-watering valuations. Traders were also looking at Washington, as the Supreme Court heard arguments over the legality of the Trump administration's tariffs.

The S&P 500 fell 0.2%, while the Nasdaq Composite shed 0.3%. The Dow Jones Industrial Average traded around the flatline.

Snap beat third-quarter revenue estimate and said it has partnered with Perplexity AI to integrate its artificial intelligence-powered search engine into Snapchat, sending the social media firm's shares up 17%.

Duolingo forecast fourth-quarter bookings below Wall Street estimates as the company prioritizes user growth and teaching quality on its app, sending its shares tumbling 25%.