Microsoft has been under audit from the IRS for the years 2004-2013. The federal agency has said that Microsoft owes an additional $29 billion in back taxes on top of the $10 billion the company had already paid. Microsoft has been under audit from the IRS for the years 2004-2013. The federal agency has said that Microsoft owes an additional $29 billion in back taxes on top of the $10 billion the company had already paid. Read More Windows Central RSS Feed