When most people think about Apple, they picture cutting-edge design, a $1,000 iPhone in their pocket, or the late Steve Jobs unveiling “one more thing.” What rarely comes to mind is the extraordinary legal structure that once allowed Apple — entirely within the law — to stockpile hundreds of billions of dollars in offshore profits, far beyond the reach of the taxman. In this article, the focus is on how Apple exploited gaps between national tax rules to minimize its effective tax rate to levels that governments and regulators now call some of the most aggressive corporate tax strategies ever deployed: the infamous Double Irish with a Dutch Sandwich . To understand how this structure emerged, it helps to start with the basics of the U.S. corporate tax regime of the time. For decades, the United States operated on a worldwide tax system , meaning American corporations were technically liable for U.S. taxes on all profits — whether earned in Boston, Berlin or Bangalore. However, this tax...