The report published by the Permanent Subcommittee on Investigations detailing Apple's strategies is a great read on its own.
The report gives an inside look on Apple's absolutely genius tax avoidance strategies.
Apple uses a variety of offshore structures and arrangements to shift billions of dollars from the United States to Ireland.
The U.S. corporate tax rate is 35%, while Apple said it has negotiated a special corporate tax rate in Ireland of less than 2%*.
(The 2% rate statement has proven controversial, see below for details)
Apple has found the secret to not paying taxes. You just avoid taxes by not declaring a tax residency for the company that oversees the entirety of your international income.
Fascinating yet weird... Apple avoids paying more in taxes, every day, than Tumblr can hope to make all year!