Question about BID vs ASK at the start of Day Trade

External question — Personal Finance Stack Exchange Author: Screaming-Cow Original post: https://money.stackexchange.com/questions/127336 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. So I have been monitoring this IPO recently. Day trade starts and we are allowed to post bid and asks for 30 minutes before the market officially opens. I see asks for around 40 for 4500 shares. Lowest ask before market open. Then I see a bid for 60 for 2000 shares. Highest bid before market open. Sample Table below: Bid-------------------------------------Ask 60$ for 2000 shares---------------------40$ for 4500 shares 59$ for 1000 shares---------------------55$ for 1000 shares 58$ for 1500 shares---------------------54$ for 1000 shares For example the list above is the latest as the market opens. Will the 40$ for 4500 shares fill in the 60$, 59$ and 58$ bids? Will it be calculated as 60 x 2000 = 120000 59 x 1000 = 59000 58 x 1500 = 87000 120000 + 59000 + 87000 = 266000$ OR...... 40 x 4500 = 180000$ ? Sorry for not so good english.