I think it will take a release of the details of the buy-out offer. But one reason for the residual bump in PPS is likely due to three things:
1- The Board has a fiduciary obligation to maximize shareholder profits - this includes considering sale at the right price. a rejection of a buy-out offer does not mean they are not for sale - this could spark more suitors now that some of the cards are out on the table.
2-Market landscape, if someone wants to park some money while things settle down where else can one easily get into and out of with a gain.
3-Less insider dumping now that we have some leadership that is actually buying instead of selling.
this play is certainly a fickle one, I had figured it to be at 12 by November and it is nowhere close enough to run there sans any news.