Think they can buy anytime, just have to report purchases when they go into the next whole per centage. They have to go for a bid once they get 30%. If they are serious about bidding, I would suspect that they are quite happy to bide time picking up relatively cheap stock from the market up to 30%, whilst behind the scenes trying to tempt a larger holder to part with a block of shares which will finally give them lift off. An institution may be tempted at the right price at this time of the year. All supposition of course.