Effectively buyers and sellers tussle for position.
Volumes at prices will determine the opening price, not just the price.
If I put 1 share to buy at $100 doesn't mean it will open at that price.
However if I bid 2,000 shares @ $100 it will only increase the price that the volume allows the price to increase to.
Vice versa for a low ball sell.
Look up the asx definition
APT Price at posting:
$67.44 Sentiment: None Disclosure: Held