Pre-Open Session

Also known as: pre open market, call auction, opening auction

The pre-open session (9:00-9:15 am) is a call auction: for 8 minutes orders are collected without executing, then the exchange computes the single price that maximises tradable quantity — the opening price. It absorbs overnight news into one orderly print instead of a chaotic first tick. Market orders placed here carry surprise risk; limit orders are the sane default.