If it was an existing large shareholder with over 5% holding...

If it was an existing large shareholder with over 5% holding then they would have to notify the market when they increased or decreased holding by 1%, so about 12.2M shares. They also have something like 5 days to put the notice in.

A new large buyer can buy over 60m shares before putting up the initial substantial holder notice, again with a lag of a 5 days if they so wish.

I've seen some large buying of shares in a company at new higher prices in the past, swallowing up everything on the ask side, just before announcing a new substantial holder notice. After they get their 5% they have 5 days to put in the notice so buy as much as possible over a few days before the market wakes up to someone big accumulating for a T/O bid. It allows a big player to not only get the first 5%, but add a couple of percent more 'early', so the initial substantial holder notice is followed up by an increase in substantial notice holding a few days later.

Assuming it's neither Beach nor Gina buying on market as they have official bids in which means they are not allowed to buy above the bid price, and we don't have a change in holding notice from anyone else yet, then the odds seem to favour someone else buying up big above the leading bid price over the last couple of weeks.

Of course it's possible that one of the large players told some rich 'friends' that they were prepared to pay up to XXc/sh at a Sunday BBQ, so they could make easy money... But IMHO the most likely thing happening is another player buying up.

Remember for a big existing gas exporter, gaining this Perth Basin gas would allow them to meet their 15% domestic committment much more easily, so it would be worth it's weight in export gas with /or without a tweaking of the current export rules (I'm not sure on this, but applying to govt could bring a quick decision allowing it). What's new export gas worth on the spot market, $US23+/Gj in Japan??

I don't think we should just consider WA pricing for the reserves here, as there are much bigger forces at play IMHO once again, so I'm just holding to see where we go...