They can only buy on market if the scheme fails and their takeover becomes unconditional (which it isn't, and based on structure, won't be until scheme of arrangement is voted or SQM pull scheme).
A person can only buy beyond 19.9% if:
1) They make a takeover offer (off-market or on-market); 2) The takeover offer is dispatched if it is off-market takeover offer (i.e. it must printed and posted) 3) the takeover offer is unconditional (on-market has to unconditional)
The only way you can buy on the first day is on-market takeover. Effectively, someone putting on an order at $3.52 to buy the remaining shares they didn't own.
AZS Price at posting:
$3.50 Sentiment: Hold Disclosure: Held