Rex
If we all knew this information, it would be easy but....
The only information available publicly is the substantial holders. You can have a look through a companies announcements, and if there is a sub holder, each time they vary their percentage by more than 1% you will see a lodgement.
You can do what that snail mail spammer does and buy records of a company's full shareholder list. Buy every company you can think of, compile it into a database and search by name to shares.