What are stock futures, and why do people check them before the market opens?

Stock index futures are contracts tied to the value of a market index like the S&P 500, the Nasdaq-100 or the Dow. The big difference from regular stock trading is the hours: the main index futures at CME trade nearly around the clock, from Sunday 6 p.m. to Friday 5 p.m. Eastern Time, with a one-hour daily break from 5 to 6 p.m. ET. Because they keep trading while the stock market is closed, futures are often the first place you see the market react to overnight news, which is why you'll hear "futures are up" or "futures are down" on morning news.

Thursday morning (Oct. 22) is a real example. After the S&P 500 closed up 0.58% on Wednesday at 7,757.17, CNBC reported early Thursday that Dow futures were down 319 points (0.6%), S&P 500 futures were down 1% and Nasdaq-100 futures were down 1.6%. CNBC tied the drop to declines in Meta and Tesla after their earnings and a jump in oil prices on rising geopolitical tensions. Two things to keep in mind: futures show where traders are pricing the market right now, not a promise of how the trading day will open or close, and futures themselves are leveraged products, so losses can be larger than the money you put in. That's why they're something to understand well before ever trading them.

Try it yourself: before the next market open, look up S&P 500 futures, then compare them with where the S&P 500 actually opens and closes that day. Got a question about futures or what moves markets overnight? Drop it below, there are no silly questions here.

Sources: CNBC market live updates, Oct. 21 and Oct. 22, 2026; CME Group, E-mini S&P 500 and equity index futures overview; Charles Schwab, E-mini S&P 500 futures contract specifications and risks.