I don't know who's selling, but I'd like to point out that now that the Saudis have made their intentions clear, they can acquire as much stock on the open market as they like -- or at least up to 20% of the shares outstanding. Ouch.
They have to file within 10 days of crossing the 5% threshold. They will have to decide whether to file as "active investors" or "passive investors" -- if they file as passive they can keep accumulating up to 20% before declaring themselves active. If they file as active they can still keep accumulating indefinitely.
But they'll want to file as passive, because if they're active, then they are potentially "obtaining control", which subjects them to CFIUS review, which is a wild crapshoot.
There seems to be an obscure Delaware rule that if you make large open market purchases you need board approval to do a squeeze-out later, but that's OK, they'll get board approval.
Tender offers and open market purchases seem to be *very* lightly regulated. The Saudis can buy up as much as they like now with no ill effects to any attempt to make a tender offer.
So, they could be scooping up as much as 20% of the stock right now.