Strangely I thought it was a week. In my experience the 2 days...

Strangely I thought it was a week. In my experience the 2 days is not tightly policed due to administrative inefficiencies. Also notice the wriggle room " 2 business days after they become aware"

http://www.companysecretary.com.au/board_briefings/SubstantialShareholders.pdf

"Therefore, under sec. 671B, any shareholder who acquires (alone or with associates) a relevant interest in 5% or more of a company’s shares must disclose that fact by lodging an ASIC Form 603 “Notice of Initial Substantial Shareholder” with the Company and the stock exchange. This lodgement requirement also extends to a shareholder making a takeover bid even if the initial holding is below 5%.

Furthermore, for each 1% (or more) change in holding a Form 604 “Notice of Change of Interests of Substantial Shareholder” must be lodged. And, if the holding falls below 5% a Form 605 “Notice of Ceasing to be a Substantial Shareholder” must be lodged.

These Forms must be lodged within 2 business days after they become aware of the transaction or change in % holding and by 9:30am next stock exchange trading day in a takeover situation."