"ASI [an Irish Apple subsidiary] buys Apple products from a Chinese manufacturer, resells them at a “substantial” markup to other Apple affiliates and retains the profits, the report said."
[1] http://www.macworld.com/article/2039299/senate-report-apple-...
Not that they're the only ones to play this game. A FMCG company I'm familiar with does something similar by having billions in raw and finished good materials owned by a Switzerland-based subsidiary for tax purposes.