US Stock Trading Rules
The US stock market provides a flexible trading mechanism that supports T+0 trading (day trade) and pre-market, after-hours, and overnight trading. It has no price limits, and the minimum trading unit is 1 share. Below is a detailed introduction.
1. Regular trading hours
| Eastern Time (ET) Eastern Time (ET) | 09:30 AM – 16:00 PM | |
| China Standard Time (CST) | 10:30 PM – 05:00 AM | Eastern Standard Time (EST) |
| 09:30 PM – 04:00 AM | Eastern Daylight Time (EDT) | |
EDT is from the second Sunday in March to the first Sunday in November each year. EST is from the first Sunday in November to the second Sunday in March the following year.
2. Trading and settlement mechanism
Day trade
Day trade is a trading mode in which customers buy and sell positions of a certain stock or stock option within the same trading day. A day trade is also commonly referred to as T+0 trading. Longbridge accounts support unlimited day trades.
Short selling rules
Short selling of US stocks is supported.
Clearing rules
The US stock market implements the T+1 settlement system, meaning that clearing and settlement are completed on the next working day after the transaction.
3. Minimum trading unit and price limit
The minimum trading unit of US stocks is 1 share (fractional shares trading is not supported for now), and there is no single-day price limit.
4. Minimum unit of stock price change
USD 0.0001 for stocks priced below USD 1; USD 0.01 for stocks priced above USD 1.
5. Pre-market and after-hours trading
US stocks can be traded before and after the regular trading hours, and pre-market and after-hours orders will be submitted to the exchange for matching. Nasdaq has special pre-market and after-hours trading hours. Each broker has different requirements for the time of pre-market and after-hours trading. Longbridge's schedules are as follows.
| Pre-market hours | 04:00–9:30 (ET) | |
|---|---|---|
| CST (for EDT): 16:00–21:30 | CST (for EST): 17:00–22:30 | |
| After hours | 16:00–20:00 (ET) | |
| CST (for EDT): 04:00–08:00 | CST (for EST): 05:00–09:00 | |
| After-hours session on early close days | 13:00–17:00 (ET) | |
| CST (for EDT): 01:00–05:00 | CST (for EST): 02:00–06:00 | |
6. Overnight trading
You can submit orders for matching during the overnight session. Any unmatched orders will be automatically canceled after the overnight session closes. On the Longbridge platform, the overnight trading schedule is as follows:
ET Sunday to Thursday 20:00–03:50 (T+1)
EDT (March–November): CST 08:00–15:50
EST (November–March of the following year): CST 09:00–16:50
Notes on overnight trading:
- Overnight trading is conducted over the counter. The upstream may impose restrictions on order prices.
- Orders for stocks involved in corporate actions within a 3-day window may be rejected by the upstream.
- Trading of the stock may be suspended on the day of, before, and after the action.
- Overnight trading is only supported for integrated accounts.
- Lower liquidity and higher volatility are common during overnight sessions. Orders may be partially filled or unfilled due to restrictions from upstream brokers or exchanges. Please carefully assess these risks.
Key takeaways:
- Trading hours
- Regular trading: 09:30–16:00 ET (CST for 21:30–04:00 EDT; CST for 22:30–05:00 EST).
- Pre-market and after-hours: 04:00–09:30 ET (pre-market), 16:00–20:00 ET (after-hours).
- Overnight trading: 20:00–03:50 ET (T+1).
- Core rules
- Day trade: unlimited T+0 trades permitted (buy and sell the same stock within one day).
- Short-selling mechanism: support the short sale of US stocks.
- Settlement system: clearing and settlement on T+1 (completed on the first working day after the trade).
- Price unit: minimum change of USD 0.0001 for stocks priced below USD 1; minimum change of USD 0.01 for stocks priced above USD 1.
- Special restrictions
- There is no limit on price fluctuations, and the stock price can fluctuate freely.
- The minimum trading unit is 1 share (fractional shares trading is not supported for now).
- Overnight trading risks: lower liquidity, larger spreads, and potential trading halts before or after corporate actions.
Disclosures
This article is for reference only and does not constitute any investment advice.
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