I checked today with the manager of GC1 - They don't have to...

I checked today with the manager of GC1 - They don't have to sell if a stock they hold goes into ASX100. They w9ont be able to add to their holding and if sold cannot purchase the stock whilst it remains in the ASX100. So, in this case, they sold APT as they deemed it to be in our interests to sell and cannot repurchase more APT stock whilst it remains in ASX100. He pointed out to me that its share price is lower than it was at the end of June.

So I think the rules do have a safeguard for holding a stock that gets picked up into the ASX100.