After-hours & pre-market trading
After-hours and pre-market trading are sessions outside the regular market day when stocks can still be traded, typically with thinner volume and wider swings.
Regular US trading runs from 9:30 a.m. to 4:00 p.m. Eastern. Pre-market trading happens before the open and after-hours trading happens after the close, both conducted on electronic networks. Big news — an earnings report or a merger announcement — often lands outside regular hours, so a stock can move sharply before most investors can react during the normal session.
These extended sessions are thinner: fewer participants means lower liquidity, wider gaps between buy and sell prices, and more exaggerated price swings. A dramatic after-hours move can partly reverse once regular trading resumes and the full market weighs in, so extended-hours prices are a noisy, preliminary signal rather than a settled one.
stocks-llm uses delayed daily-close prices, shown with their as-of date — it does not provide real-time, after-hours, or pre-market quotes. This definition is educational only.
See more terms in the stocks-llm glossary.
Informational only — NOT financial advice. This is an educational definition, not a recommendation to buy or sell anything. Metrics on stocks-llm are delayed data and may be missing or stale. Always verify information independently and consult a qualified financial professional before making any investment decision.