Microsoft revealed on Wednesday that it received a notice from the U.S. Internal Revenue Service (IRS) in September, demanding an additional tax payment of $28.9 billion, along with penalties and interest for the tax years between 2004 and 2013. The dispute centers on how Microsoft allocated its profits across various countries and jurisdictions. The company stated it has altered its practices to make them compliant with current regulations, making the IRS concerns relevant to the past. Microsoft believes that potential taxes owed could be reduced by as much as $10 billion under tax laws enacted during the previous administration. The company plans to contest the IRS’s findings, starting with an internal IRS process and possibly proceeding to court if necessary. The IRS has not confirmed or denied the audit due to U.S. legal restrictions.