In October 2023, Microsoft disclosed that the U.S. Internal Revenue Service was seeking about $28.9 billion in back taxes, plus penalties and interest, over how the company allocated profits among countries between 2004 and 2013 — years when Bill Gates was Microsoft's chairman. The dispute centers on 'transfer pricing,' including a Puerto Rico manufacturing arrangement that the IRS said let Microsoft shift a large share of U.S. revenue into lower-tax jurisdictions. Microsoft said it disagreed with the IRS's position, believed it had followed the rules, and would contest the claim through the agency's appeals process and potentially the courts — a fight expected to take years. It ranks among the largest tax disputes in U.S. corporate history.