Trading Venue calendars, sessions, and operator overrides

Give a market an IANA timezone, a weekly session template, and dated exceptions so it opens through a preopen auction and closes on schedule, and override the calendar when a session must move.

A trading calendar turns a continuously trading market into a session-aware one. You give the market an IANA timezone, a weekly template with preopen, open, and close times per traded weekday, and dated exceptions for holidays and half-days. From then on, the platform runs the sessions automatically. Orders collect during preopen with a live indicative price, the book opens through a call auction at a randomized instant inside the published window, and the session closes with an official closing price. A market without a calendar trades continuously around the clock.

Before you start

You hold the venue-operator role: platform administrator or organization owner.
The market is listed. Continuous and auction-only markets both take calendars; an auction-only market needs one to trade at all.

What the calendar drives

Phase	Trigger	What the market does
Preopen	The template's preopen time	Orders collect with reservations, no matching. The indicative auction price and matchable quantity publish live.
Open	A randomized instant within the venue's published window after the scheduled open time	The book uncrosses once at the uniform clearing price. The remainder rests at its original price-time priority, and continuous matching begins.
Closed	The template's close time	New orders are refused. The official closing price is computed and published. Good-till-cancelled orders and their reservations persist to the next session.

Session transitions behave like a halt at the boundary: they stop matching and new order acceptance, cancel nothing, and let already-staged settlement batches complete. The trading screen shows traders the session state and the next scheduled transition.

The exact opening instant is deliberately unpredictable. The calendar publishes the scheduled open time and the width of the uncross window; the drawn instant inside that window is never disclosed, so nobody can game the last moment before the uncross.

Set the calendar

Open the calendar editor

Go to Venue operations, open the market, and open Trading calendar.

Choose the timezone

Pick the market's IANA timezone, for example Europe/Brussels. All template times are wall-clock times in this zone, and they stay at the same wall-clock hour across daylight-saving changes.

Fill the weekly template

For each traded weekday, set the preopen, open, and close times, for example preopen 08:00, open 09:00, close 17:30. A weekday without a row has no session, so leave the weekend empty for a five-day market. Times must satisfy preopen before or at open, and open before close.

Add dated exceptions

Add a closed exception for each holiday: that date has no sessions at all. Add an open exception with its own times for a half-day: those times replace the weekday template for that date.

Save

Save the calendar. Upcoming sessions materialize from it, and the market detail shows each occurrence with its scheduled boundaries and, after the close, the session's official closing price.

Override a session

Overrides are calendar edits that take effect from now. There is no separate override object to manage or clean up.

Goal	Edit
Delay today's open	Add an open exception for today with a later open time.
Extend today's session	Add an open exception for today with a later close time.
Close early	Add an open exception for today with an earlier close time.
Cancel today's sessions	Add a closed exception for today.

Sessions that have not started re-materialize from the edited calendar, and an in-progress session is re-bounded. Manual halt and resume stay available in every session state as a separate control; a halt never touches the calendar.

The official closing price

At each close, the market computes an official closing price by the methodology set on the market's settings. The methodology is the last settlement-confirmed trade of the session, or a volume-weighted average price over a configured window before the close. Busted trades are excluded. The close publishes to the platform's price-feed infrastructure as a new observation marked as the official close, and it anchors the next session's static price band. A session without trades publishes no close.

Troubleshooting

Issue	What to check
The market never leaves closed	The weekly template has no row for today's weekday, or a closed exception covers today.
The open happened later than the open time	That is the design: the uncross happens at an undisclosed instant within the published window after the scheduled open.
A holiday session still ran	The exception date must be the market's local date in its timezone, not your own.
Orders are refused outside the session	That is the design: a closed market refuses new orders. Resting good-till-cancelled orders persist and their expiries keep running.

Trading venue market structure for the session and auction model behind the calendar
Run private markets for auction-only markets with restricted participation
Set price bands and thresholds for the static band the session anchors
Trade through sessions and auctions for the API view of sessions and the calendar

Configure trading calendars