How Do TXSE Opening, Closing and Halt Auctions Work?

As of October 2026, the Texas Stock Exchange (TXSE) runs an Opening Auction at 9:30 a.m. ET, a Closing Auction at 4:00 p.m. ET and a Halt Auction after regulatory halts for the securities it lists, and the prices from those auctions become the TXSE Official Opening Price and Official Closing Price. The details sit in TXSE Rule 11.022: on-close orders are accepted until 3:58 p.m. and cannot be changed or canceled in the final two minutes, and a halted TXSE stock reopens through an auction that starts with a five-minute Quote-Only Period. Several of these rules changed in July and September 2026, so older summaries are out of date.

How do Texas Stock Exchange auctions work?

TXSE is now the listing exchange for a growing group of stocks and ETFs, and for those securities it sets the official open, the official close and the reopening price after a halt. The current list, with start dates, is in hi2morrow's guide to which stocks and ETFs are listed on the Texas Stock Exchange. The rules are in TXSE's rulebook, updated as of September 16, 2026, mainly Rule 11.022 for the auctions and Rule 11.020H for regulatory halts.

Two details of the schedule shape everything that follows. TXSE accepts orders from 8:00 a.m. to 5:00 p.m. ET, with the Pre-Market Session from 8:00, regular hours from 9:30 to 4:00 and a Post-Market Session until 5:00, so there is no 4:00 a.m. start and no after-hours trading until 8:00 p.m. as on some other venues. And an auction produces a single price at which all matched auction orders execute together, rather than a series of trades at moving prices.

Two recent changes explain why search summaries often disagree with the rulebook. The SEC approved SR-TXSE-2026-006 on July 24, 2026, which moved the on-close cutoff from 3:59 to 3:58 p.m. and added Participation Bands. SR-TXSE-2026-032 took effect on filing on September 15, 2026 and changed how orders are handled in a halt. Like any immediately effective filing, it remains open to SEC review, so the details could still change.

What is the TXSE closing auction timeline?

The closing auction has three stages, and the cutoff that matters is 3:58 p.m. ET. From 3:00 to 3:58 p.m., TXSE publishes the projected Matched Shares and the Offset Side every five seconds. Market-on-close (MOC) and limit-on-close (LOC) orders can be entered until 3:58, and from that minute no auction order can be modified or canceled until the cross at 4:00.

From 3:58 to 4:00 p.m., TXSE publishes the Participation Bands and the auction interest at each band instead. Only late limit-on-close orders (LOC.L) are accepted in this window. They cannot be amended or canceled after entry, and if their limit is more aggressive than the Upper or Lower Band, the price is moved to the band just before the auction. At 4:00 the auction runs at one price, which for a corporate security becomes the TXSE Official Closing Price. Unexecuted MOC, LOC and LOC.L orders are canceled after the auction, while limit orders resting in the continuous book move to the Post-Market Session.

TXSE's cutoff falls later than the big incumbents'. Nasdaq stops accepting MOC orders at 3:55 p.m. and freezes cancellation from 3:50, and the NYSE applies a 3:50 p.m. cutoff under its published interpretation. The reasons the market gets busy at that time are covered in hi2morrow's guide to why volume spikes at 3:50 p.m. ET. On both of those exchanges the cancellation freeze lasts ten minutes, while TXSE's lasts two. Your broker may set an earlier cutoff than the exchange or may not offer on-close orders at all, so check its own rules.

How does the TXSE opening auction work?

The opening auction mirrors the close with different clock times. Market-on-open (MOO) and limit-on-open (LOO) orders are accepted from 8:00 a.m. until 9:28 a.m. ET, after which new ones are rejected. From 9:28 to 9:30 only late LOO orders (LOO.L) are accepted, and eligible auction orders can no longer be changed or canceled. TXSE publishes Matched Shares and the Offset Side every five seconds from 8:00 to 9:28, and Participation Bands from 9:28 to 9:30.

In priority, MOO orders and market orders for the regular hours come first. When the auction runs at 9:30, the result is the TXSE Official Opening Price. LOO, LOO.L and MOO orders that do not execute are canceled right after it, while limit orders in the continuous book stay live.

The price cannot go anywhere. It has to fall inside a Collar Price Range around a midpoint taken from the national best bid and offer: plus or minus 10% when the midpoint is $25 or less, 5% between $25 and $50, and 3% above $50. Within that range, the exchange picks the price that executes the most shares.

How are TXSE auction prices set, and what are Participation Bands?

The price rule is a sequence of tests. TXSE picks the price inside the collar that executes the largest number of shares across the auction book and the continuous book. If several prices tie, it takes the one with the smallest imbalance, then the price of an entered order with unexecuted shares, and finally the price closest to a reference value such as the NBBO midpoint. The SEC's approval order describes this tiebreaker as substantively identical to Nasdaq's.

Participation Bands limit where late limit orders can take part in the last two minutes. According to Rule 11.022, a band is built from the median of recent prices plus or minus a multiple of the median absolute deviation, and the exchange sets the parameters in a circular. The rule only fixes the permitted ranges, such as a window of 2 to 30 minutes and a maximum half-width of 1% to 5% on each side. Specific numbers are not stated here because they are set by the exchange outside the rulebook.

You can watch this live. On October 7, 2026, TXSE launched a public Auction Viewer in beta. It shows projected matched shares and the side with excess interest every five seconds from 8:00 to 9:28 a.m. and 3:00 to 3:58 p.m., and the bands with the buy and sell shares at each edge from 9:28 to 9:30 and 3:58 to 4:00. The share counts reflect auction-only orders and exclude the continuous book, so they show part of the picture and do not by themselves tell you the closing price.

What happens to open orders when a TXSE-listed stock is halted?

When TXSE halts a stock it lists, the order book is not wiped, but the handling is different for each order type. Under Rule 11.020H, resting orders are repriced to their limit price, all cancellations are accepted, immediate-or-cancel orders are rejected, and other instructions are accepted within the halt auction rules. The filing that took effect on September 15, 2026 added three specifics: non-displayed limit orders stay in the book and take part in the halt auction, pegged orders remain in place but cannot execute until an NBBO is available after the auction, and market orders no longer qualify for an intraday halt auction.

That last point follows from how TXSE defines market orders, which can only be entered as immediate-or-cancel. Because those are rejected during a halt, the only order type that can be entered during the Quote-Only Period of a halt auction is a limit order. Anything else you send will be turned back.

A different case is an operational halt, declared for a technical reason. Under Rule 11.020H(c)(3), TXSE cancels all unexecuted orders in the security, including auction-only orders. For the general mechanics of what a broker does with your order on top of the exchange's own handling, see hi2morrow's guide to what happens to open orders during a trading halt. A halt by the listing exchange is observed by all U.S. markets, as FINRA explains.

How does a halted TXSE stock reopen?

A regulatory halt ends with a Halt Auction that is preceded by a Quote-Only Period beginning five minutes earlier. During that period TXSE publishes the Halt Auction Collars and the auction interest outside them every five seconds, and eligible orders can be canceled at any moment before execution.

The collars start from a reference price. After a halt that was not a limit up-limit down pause, the reference is the last eligible trade before the halt, and the collars sit 5% on each side, or $0.15 when the reference is $3.00 or less. After a LULD Trading Pause, the reference is the price band that triggered the pause, with the collar 5% beyond it and the opposite band as the other limit. If the price that would clear the auction falls outside the collar, the Quote-Only Period is extended by five minutes and the collar widens by another 5% toward that price, and this repeats until the auction can run.

The cutoff is 3:50 p.m. ET. If the halt is called between 3:50 and 4:00, or the extensions would run past 3:50, no halt auction takes place. TXSE runs a Volatility Closing Auction at 4:00 instead, whose result is the Official Closing Price. After a Level 3 market-wide circuit breaker, TXSE does not use a halt auction either.

What does a TXSE auction look like for a stock like ABC?

Take ABC, a made-up stock listed on TXSE, with a National Best Bid and Offer of $39.98 by $40.02 at 3:50 p.m. ET. The midpoint is $40.00, so the 5% collar range runs from $38.00 to $42.00. At 3:00 p.m. the Auction Viewer shows 120,000 Matched Shares with the Offset Side on the buy side. At 3:57:30, a trader enters a MOC order to sell 300 shares, and it is accepted. At 3:58:10 the trader changes their mind, but the cancel request is refused, because auction orders are frozen from 3:58. A buy LOC.L at $41.50 entered in the last minute would be moved to the Upper Band, say $40.30. At 4:00 the auction clears at $40.05, which becomes the TXSE Official Closing Price, and the trader's MOC sells at that price. A MOC order is never guaranteed a fill, but in this case it was matched.

The next day at 11:02 a.m., TXSE halts ABC on news. The last eligible trade was $40.00, so the starting collars are again $38.00 and $42.00. The trader has a resting limit buy for 200 shares at $39.50, a non-displayed limit sell and a midpoint-pegged order. The first two stay in the book, with the non-displayed order eligible for the auction, and the pegged order waits for a new NBBO. The Quote-Only Period runs from 11:40 to 11:45. A market order sent at 11:41 is rejected. Buy interest pushes the clearing price to $43.50, outside the collar, so the period extends to 11:50 and the upper collar rises to about $44.00 in this illustration. The auction runs at $43.50 and continuous trading follows. Had the halt lasted past 3:50 p.m., the stock would have closed through the Volatility Closing Auction instead.

Alexander Styopin's professional view: the new lock at 3:58 matters more than the three-minute difference suggests. On other exchanges a trader who changes their mind has until 3:50 or 3:55, on TXSE the window is almost to the end, and that makes it easy to assume a cancel will go through. In practice, treat 3:57 as the last time you can change a close order, and in a halt remember that a limit order is the only thing the exchange will accept in the last five minutes. A halt can open far from the last print, so a stop-loss or a resting order set earlier is no protection for the reopening price.

Educational material only. Not investment or legal advice. Order handling, margin, and settlement rules can vary by broker, account type, and jurisdiction, and exchange rules may change.

Author: Alexander Styopin, hi2morrow analyst and economist with 25 years of experience in the US stock market