Pre-open calls
Rest a call on a Window before it opens for trading; taker orders are refused until the bell.
Because Windows are prelisted ahead of time (see Sessions and lanes), you can place a call before the market — or the Monday Gap, or a Window's own trading start — actually opens. This is a resting, post-only call, not an instant trade: nothing fills before the Window's trading start, by design.
Where to schedule one
While the stock market is closed, the /markets board lists each company's next Windows under Schedule a call. Choose a Window length, then Call Up or Call Down to open the pre-open ticket at your price. On Short, a stock Window that opens later offers Schedule a Down call on the same terms.
How it works
A Window before its trading start is in a Listed state. In that state, the venue only accepts PostOnly orders — an order that rests on the book rather than taking. A taker-type order (IOC, FOK, or a Normal order that would cross immediately) is refused outright with a PreOpenTakerRefused error, so nobody can jump the queue by trading against a resting pre-open call before the bell.
What happens at the open
Once the Window opens for trading, resting pre-open calls become ordinary resting orders: the venue's own seed maker or any other trader can fill them at their resting price, same as any other order on the book.
- Default expiry: a scheduled call expires 90 seconds after the trading start if nothing has filled it — "fills within the first minute after the bell, or your stake returns." This is the default so a stale call from hours earlier doesn't linger unexpectedly.
- Resting until the lock is available as an explicit opt-in, if you'd rather leave the call open for the whole Window instead of just the first minute.
What's guaranteed and what isn't
- Nothing fills before the open boundary — that's enforced by the program, not just the UI.
- No fill is promised. A pre-open call is an offer at your price; it fills only if the book comes to it.
- If the Window voids for any reason, an unfilled pre-open call loses nothing — cancel it any time before it fills, and the escrow (plus the seat bond) comes straight back.