Ace has 15% (he had 10 before his “date” with Rosa Cartman, so Uncle Gary must have made good on increasing his share).  With Larry and Ace’s mom owning 20% each, that leaves Uncle Gary with 45%.

That’s not “controlling interest” but he is the majority share holder and he would have enjoyed Larry’s, and perhaps Ace’s mom’s, backing until now.  If he’d never given Ace that extra 5% he’d still have control, but he doesn’t seem bitter about that.