What Happens When the Market Is Closed?
The last available quote, official close, and overnight trading can describe different moments and venues.
Read the draftTrading Concepts
Why Pre-Market, Regular, and After-Hours Data Can Differ
Prices outside regular U.S. equity hours may come from different sessions, fewer participants, and a different mix of venues. The most recent trade is not always the official regular-session closing price.
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Identify the session
For Nasdaq-listed equities, the published regular session is generally 9:30 a.m. to 4:00 p.m. Eastern on trading days; Nasdaq also identifies pre-market and after-hours sessions. Holidays and early closes change the schedule. Check the current exchange calendar before interpreting a timestamp.
Expect different market conditions
Outside regular hours, available volume and displayed liquidity can be thinner, with wider spreads and sharper jumps. A price from one exchange's feed may not capture activity elsewhere. That is especially important when comparing an IEX feed with consolidated SIP data.
Do not mix reference prices
A stock's overnight last trade, a regular-session close, and a cash index's official close refer to different moments. Keep the reference label visible. A gap at the next regular open describes the distance from the previous close to that open; it does not show a continuous path between them.
Sources and further reading
- Nasdaq Stock Market Holiday Schedule and Trading HoursRegular and extended-hours session definitions
- Alpaca Market Data FAQFeed coverage, entitlements, and recent historical data