Jason Isaacs was being held short by a lot of players for his 11/11/14 adjust where he dropped a Harry Potter movie and added Fury.
After that adjust, some ports started dumping their shorts (which casued the price to go upwards) while other players kept their shorts for his next planned adjust that would drop Cars 2 and add After The Fall.
After The Fall has been released, but has not reported any box office (and is not likely to) so *that* adjust is not likely to happen, so more players have been dumping their shorts (causing the price to keep moving upwards) since the date of his next adjust is currently unknown.