Board Thread:Wiki discussions and announcements/@comment-26053782-20150129202217/@comment-3974211-20150208195354

The bonuses stack cyclically, in case that hasn't been raised.

Let's say I have 100 AP. Rabadon's grants me 30 AP and Aspect of the Serpant grants me another 30 AP. Rabadon's then increases Aspect's 30 by 30% and vice verse, granting another 9 AP each. Same again. Repeat until the amount gained is unnoticeably small. Two 30% bonuses stack for a total increase of ~85.7%.