What is premarket trading?
Premarket trading is the part of the US trading day that comes before the regular session. Stocks can trade on US exchanges from 04:00 ET, four in the morning in New York, until the opening bell at 09:30 ET. Together with after-hours trading in the evening, it makes up what brokers call extended hours.
For small-cap day traders, the premarket is where the day starts. A company that releases news overnight or early in the morning can gap up or down long before the open, and the stocks that will be most active after 09:30 often show themselves first in the premarket: a large gap, far more volume than usual, a price that keeps climbing. The premarket gap scanner guide covers how traders find them.
Trading before the open is different from trading after it:
- Fewer traders. Volume is a fraction of what it is in the regular session, especially in the first hours.
- Wider spreads. The distance between the best bid and the best offer is often larger, so getting in and out costs more.
- Limit orders. Many brokers only accept limit orders outside the regular session.
Premarket hours in New York time
US market hours are set in New York time, ET, which moves with daylight saving time. These are the sessions of a normal trading day:
| Session | New York time (ET) |
|---|---|
| Premarket | 04:00 to 09:30 |
| Regular session | 09:30 to 16:00 |
| After-hours | 16:00 to 20:00 |
Two things change this in practice. Your broker decides which part of extended hours you can trade: some open their premarket at 04:00 ET, others later in the morning, so the hours in your platform may be shorter. And on days the market is closed for a holiday there is no premarket at all, while on the few days the regular session closes early, at 13:00 ET, the morning runs as usual. Some brokers also offer an overnight session, from 20:00 to 04:00 ET, usually on a limited list of stocks; it comes before the premarket and is not part of it.
Premarket hours in your time zone
If you trade from outside New York, the premarket starts at another time on your clock. In cities that change their clocks on the same dates as New York, the difference stays the same all year:
| City | Premarket | Regular session |
|---|---|---|
| New York | 04:00 to 09:30 | 09:30 to 16:00 |
| Chicago | 03:00 to 08:30 | 08:30 to 15:00 |
| Los Angeles | 01:00 to 06:30 | 06:30 to 13:00 |
London and Madrid also change their clocks, but on other dates, so this is their premarket for most of the year, with the exceptions in the next section:
| City | Premarket | Regular session |
|---|---|---|
| London | 09:00 to 14:30 | 14:30 to 21:00 |
| Madrid | 10:00 to 15:30 | 15:30 to 22:00 |
Mexico City, Bogotá, Lima and Buenos Aires don't change their clocks, so the premarket moves by an hour on their clock whenever New York changes its own. New York is on summer time from the second Sunday of March to the first Sunday of November:
| City | Premarket, New York summer | Premarket, New York winter |
|---|---|---|
| Mexico City | 02:00 to 07:30 | 03:00 to 08:30 |
| Bogotá and Lima | 03:00 to 08:30 | 04:00 to 09:30 |
| Buenos Aires | 05:00 to 10:30 | 06:00 to 11:30 |
In every city, the regular session starts when the premarket ends and lasts six and a half hours.
The weeks when the difference changes
The US moves its clocks forward on the second Sunday of March, and Europe on the last Sunday of March. In the autumn, Europe moves back on the last Sunday of October, and the US on the first Sunday of November. In the weeks between, Europe is an hour closer to New York, and the premarket starts an hour earlier on a European clock:
| Trading days | London | Madrid |
|---|---|---|
| March 9 to 27, 2026 | 08:00 to 13:30 | 09:00 to 14:30 |
| October 26 to 30, 2026 | 08:00 to 13:30 | 09:00 to 14:30 |
| March 15 to 26, 2027 | 08:00 to 13:30 | 09:00 to 14:30 |
| November 1 to 5, 2027 | 08:00 to 13:30 | 09:00 to 14:30 |
The regular session moves with it: in those weeks it opens at 13:30 in London and at 14:30 in Madrid.
In Mexico City, Bogotá, Lima and Buenos Aires, the change comes on the US dates instead: the premarket starts an hour earlier on their clock from the second Sunday of March, March 8 in 2026 and March 14 in 2027, and an hour later again from the first Sunday of November, November 1 in 2026 and November 7 in 2027.
If you set an alarm for the premarket, these are the dates to move it.
How small caps trade in the premarket
The first hours after 04:00 ET are usually the quietest. A small cap with no news may not trade at all, and one that does can print a few hundred shares at a time, minutes apart. Volume tends to build as the open gets closer, and around news: many companies release theirs before the open, and the stocks they move can trade more in the premarket than they usually do in a whole day.
Traders read a few things from the premarket:
- The gap. It is measured from the previous close to the session's first trade, which can come at any time from 04:00 ET. A stock that gapped up and kept climbing is a different situation from one that gapped up and has been sliding since its first trade.
- The premarket high and low. Many traders mark them as levels for the open, and the setup known as gap and go is built around a break of the premarket high.
- No volatility pauses. The limit up-limit down pauses only apply from 09:30 ET, so a small cap can run much further in the premarket without stopping. The guide to trading halts explains what changes at the open.
Planning your morning from another time zone
Where you live decides what kind of trader's morning you get. In Europe, the premarket falls in your working day, and the regular session in your evening. In Mexico City or Bogotá, it starts in the middle of the night, and the open comes at breakfast time. On the US West Coast, the premarket starts at 01:00 and the open comes at 06:30.
A few habits make that easier:
- Set your alarms by New York time. Work out your premarket and your open from the tables above, and move them on the dates in the previous section.
- Know what your screen shows. Traderly's market data is delayed 15 minutes, so at 10:15 in Madrid its scanner shows the premarket as it was at 10:00, which for most of the year is 04:00 ET, the very start of the session. That is enough to build and study a watchlist, not to time an entry.
- Study the hours you can't watch. If the premarket falls while you sleep, you can still see how it unfolded: the guide to practicing day trading covers how to replay past sessions, premarket included, at whatever time suits you.