Equity Raise - price action?

What happens when an equity raise takes place.

I mean for example IAG and PMO.

Two companies clearly state they want to raise equity in advance. My question is, is this already priced in after the announcement or do you see a price drop after dilution?

Never been involved in one as I’m new to trading. I understand there won’t be a glove that fits all but in general how does it work?