I have a feeling from some where in the back of my brain that...

I have a feeling from some where in the back of my brain that once a company makes an public/official offer they cannot buy shares in the company as in 'make an aggressive take over by stealth" as it would be seen as possible manipulation and then the offer would be 'unclean/not genuine' and I remember with RIO? that once they had placed an offer there was also either a limited number of attempts allowed and/or a time restriction on when they could make a take over again. I am sure the rules would be extensive and complex to ensure that companies can operate without too much interference and be able to remain stable to plan their future. As for the 'not in Australia's best interests' that's another question that only the Gov't of the day can answer. Any other comments welcome to clarify the question put here. Cheers.