• The Federal Reserve cut its key interest rate by a quarter percentage point.
• The Supreme Court said it will hear arguments challenging a law that could lead to a ban of TikTok.
• OpenAI released a new way consumers can talk to its viral chatbot, 1-800-CHATGPT.

Here are five key things investors need to know to start the trading day:

1. A sobering reality

Stock futures were slightly up Thursday morning as investors absorbed the Federal Reserve's revised outlook for interest rates next year. S&P 500 futures jumped 0.42%, while futures tied to the Dow Jones Industrial Average rose 0.39% and Nasdaq 100 futures climbed 0.33%. Follow live market updates.

2. Fed rate cuts

The Federal Reserve on Wednesday cut its key interest rate by a quarter percentage point and indicated a more cautious approach to additional cuts in the future. The Fed said it anticipates only two more cuts in 2025, two less than what it had expected in September. "Today was a closer call but we decided it was the right call," Fed Chair Jerome Powell said at his post-meeting news conference. The Fed rate sets what banks charge each other for overnight lending but also influences consumer debt, including mortgages, credit cards and auto loans.

3. TikTok's last chance

The Supreme Court on Wednesday said it will hear arguments challenging a law that could lead to a ban of ByteDance's social media app TikTok. The Supreme Court scheduled oral arguments in the case for Jan. 10, nine days before the law is set to take effect. The law would require ByteDance to sell the app or force Google, Apple and other platforms to stop supporting the app in the United States. The app has skyrocketed in popularity in recent years and is used by an estimated 170 million Americans.

4. 1-800-CHATGPT

OpenAI on Wednesday released a new way consumers can talk to its viral chatbot, 1-800-CHATGPT. At first, the company said users will get 15 minutes free per month and can access the features by dialing the U.S. number (1-800-242-8478) or messaging it via WhatsApp. The news follows a slew of updates from OpenAI as part of a 12-day release event, including the official announcement of Sora, OpenAI's buzzy AI video-generation tool. The announcements are part of an aggressive growth plan for OpenAI as it battles a growing number of competitors in a market that is predicted to top $1 trillion in revenue within a decade.

5. Shutdown on the horizon

President-elect Donald Trump on Wednesday opposed a Republican-backed government funding bill, raising the odds of a government shutdown. A source familiar with the president-elect's thinking confirmed that Trump told a Fox News host he is "totally against" the continuing resolution. Trump's opposition comes after Elon Musk tried to tank the 1,547-page bill throughout the day, which he says is laden with wasteful pork-barrel spending. If no legislation is passed by the House and Senate and signed by President Joe Biden after Friday night, the federal government would enact a partial shutdown that could include employee furloughs.

— CNBC's Pia Singh, Jeff Cox, Dan Mangan, Hayden Field and Kevin Breuninger contributed to this report.