Overnight Stock Trading Rules: What Changes on December 6

Place a limit orderLimit OrderA limit order is an instruction to buy or sell a security at a specified price or better — a buy limit will only execute at your price or lower, a sell limit will only execute at your price or higher, guaranteeing the price but not the fillRead definition → at 11 p.m. on Nasdaq's new overnight session, and it's gone at 4 a.m. if it hasn't filled. That's one of the overnight stock trading rules that will surprise traders when US exchanges start running 23 hours a day on December 6.

The new session looks like an ordinary market on your screen, but it runs on its own rules. A trade on Monday night carries Tuesday's date. A market orderMarket OrderA market order is an instruction to buy or sell immediately at the best available price — it guarantees execution but not the price, meaning in fast or illiquid markets you can receive a significantly worse fill than the last quoted price.Read definition → won't work. And a cheap stock can swing much further than the headline 20% band suggests. Here's what actually changes, with the numbers you need before you place your first trade after 9 p.m.

Overnight stock trading on US exchanges is scheduled to start at 9:00 p.m. ET on Sunday, December 6, 2026. The session then runs from 9:00 p.m. to 4:00 a.m. ET, Sunday through Thursday nights, and connects to the existing premarket session at 4:00 a.m.

The SEC has conditionally approved 23-hour trading on five exchanges: Nasdaq, NYSE Arca, Cboe, MEMX and 24X. The launch depends on the consolidated data feeds being ready, and exchange representatives said at the SEC's September 17 roundtable that they remain on track. Nasdaq still describes December 6 as the expected date, pending that readiness and any applicable rule changes.

"23/5" doesn't mean the market never stops. Here's the full week on Nasdaq and NYSE Arca:

The weekend gapGapA gap is a price discontinuity on a chart where a stock opens significantly higher or lower than the previous session's close, leaving a visible empty space — gap-ups are driven by overnight buying pressure or positive news; gap-downs by seRead definition → isn't going anywhere. News that breaks on a Saturday still has to wait until Sunday night. For a full history of how the market got here, read our guide to 23-hour trading. For how the older sessions fit together, see stock market hours explained.

Only limit orders work in the overnight session. All five exchanges plan to accept only orders that carry a limit price, because thin trading makes unpriced orders more dangerous.

Nasdaq's FAQ lists what it won't take between 9 p.m. and 4 a.m.: market orders, pegged orders, and orders meant for the opening or closing auctions, such as market-on-open and limit-on-close.

A limit order is an instruction to trade only at your price or better. If the price never reaches you, you don't trade. Our guide to order types covers how that differs from market and stop orders.

That has a cost for your risk plan. A standard stop orderStop OrderA stop order (also called a stop-market order) becomes a market order and executes immediately at the best available price once the stock touches or crosses your specified stop price — it guarantees execution once triggered but not the fillRead definition → becomes a market order when triggered, and a market order has no place in this session. AskAskThe ask is the lowest price a seller is currently willing to accept. When you buy with a market order, you pay the ask.Read definition → your broker exactly what happens to a stop after 8 p.m. If it won't work overnight, reduce your size so that a sharp move can't do serious damage.

On Nasdaq, every order entered between 9 p.m. and 4 a.m. that's still open at 4 a.m. is canceled. You can enter it again for the session that follows.

This catches traders who assume "good till canceled" means the order will survive. Nasdaq accepts most time-in-force settings overnight, but says all orders entered in the session are canceled when it ends. Your broker may handle this differently on its side, so check before you rely on it.

The overnight session also doesn't open with an auction. NYSE Arca says trading simply begins at 9:00 p.m., and the first auction of the day is still its 4:00 a.m. Early Open Auction. There's no single opening price to anchor your plan, and early prices can be messy.

Overnight price bands are fixed limits around two reference prices, and trades and displayed prices can't fall outside them. The lower band sits 20% below the lower reference price, and the upper band sits 20% above the higher one. The bands don't update during the session.

The two reference prices are the stock's official closing price and an evening last-sale price. There's also a minimum width of $3 from the reference price for stocks closing at $1 or more, and $1 for stocks closing below $1. That minimum is the detail most traders miss.

Look at that $4 stock. The "20%" band actually allows a move of 75% in either direction. Cheap stocks have far less protection than the headline number suggests. For leveraged exchange-traded products, the percentage and minimum are multiplied by the leverage ratio, so a 3x fund gets a 60% band.

Hitting a band doesn't pause trading automatically. The listing exchange can declare a halt to keep trading orderly, but a stock halted overnight won't reopen during the overnight session. That's a real difference from regular hours, when limit up-limit down pauses usually end within minutes.

Some stocks get halted overnight because the one-hour pause isn't long enough to process complex corporate actions. Listing exchanges will halt affected stocks from the 8:00 p.m. to 9:00 p.m. pause before the event's effective date, and reopen them at 8:00 a.m. ET.

The covered events include symbol or CUSIP changes, large dividends, stock splits, de-SPAC deals, spin-offs, security type changes and mergers. On Nasdaq, a large dividend means 25% or more of the prior official close.

If you hold a stock going through one of these events, you can't exit it overnight. Check the corporate actions calendar before you assume the overnight session gives you a way out.

Separately, if a market-wide decline triggers a Level 3 circuit breaker, trading doesn't resume until 4:00 a.m. ET the following day.