I don't think Apple has their own fab, but at this point since they have both the chip volume and cash on hand to make it happen, I don't see why they don't build their on chip fabs. I know easier said than done, but they have the resources to move mountains if they wish.
Apple has cash because they have, to date, been smart enough to avoid getting into capital intensive production and manufacturing.
Being vertically integrated (an IDM, i.e. owning your fabs) is not a path to riches unless you also happen to be able to operate as a virtual monopoly on the products you are selling.