Elphicke published research on October 30, 2012, which showed that some multinational companies, including Apple Inc., were making billions of pounds of profit in the UK, but were paying an effective tax rate to the UK Treasury of only 3 percent, well below standard corporate tax rates. He followed this research by calling on the Chancellor of the Exchequer George Osborne to force these multinationals, which also included Google and The Coca-Cola Company, to state the effective rate of tax they pay on their UK revenues. Elphicke also said that government contracts should be withheld from multinationals who do not pay their fair share of UK tax. According to a US Senate report on the company's offshore tax structure concluded in May 2013, Apple has held billions of dollars in profits in Irish subsidiaries to pay little or no taxes to any government by using an unusual global tax structure. The main subsidiary, a holding company that includes Apple's retail stores throughout Europe, has not paid any corporate income tax in the last five years. "Apple has exploited a difference between Irish and U.S. tax residency rules", the report said. On May 21, 2013, Apple CEO Tim Cook defended his company's tax tactics at a Senate hearing. Apple says that it is the single largest taxpayer in the U.S., with an effective tax rate of approximately of 26% as of Q2 FY2016. In an interview with the German newspaper FAZ in October 2017, Tim Cook stated that Apple was the biggest taxpayer worldwide. In 2016, after a two-year investigation, the European Commission claimed that Apple's use of a hybrid Double Irish tax arrangement constituted "illegal state aid" from Ireland, and ordered Apple to pay 13 billion euros ($14.5 billion) in unpaid taxes, the largest corporate tax fine in history. This was later annulled, after the European General Court ruled that the Commission had provided insufficient evidence. In 2018, Apple repatriated $285 billion to America, resulting in a $38 billion tax payment spread over the following 8 years. Charity Apple is a partner of (PRODUCT)RED, a fundraising campaign for AIDS charity. In November 2014, Apple arranged for all App Store revenue in a two-week period to go to the fundraiser, generating more than US$20 million, and in March 2017, it released an iPhone 7 with a red color finish. Apple contributes financially to fundraisers in times of natural disasters. In November