Google Inc. cut its taxes by $3.1 billion in the last three years using a technique that moves most of its foreign profits through Ireland and the Netherlands to Bermuda.

To reduce its overseas tax bill, Google uses a complicated legal structure that has saved it $3.1 billion since 2007 and boosted last year's overall earnings by 26 percent. While many multinationals use similar structures, Google has managed to lower its overseas tax rate more than its peers in the technology sector.

Irish law makes it difficult for Google to send the money directly to Bermuda without incurring a large tax hit, so the payment makes a brief detour through the Netherlands, since Ireland doesn't tax certain payments to companies in other European Union states. Once the money is in the Netherlands, Google can take advantage of generous Dutch tax laws. Its subsidiary there, Google Netherlands Holdings, is just a shell (it has no employees) and passes on about 99.8 percent of what it collects to Bermuda. (The subsidiary managed in Bermuda is technically an Irish company, hence the "Double Irish" nickname.)

The U.S. corporate income-tax rate is 35 percent. In the U.K., Google’s second-biggest market by revenue, it’s 28 percent.