The IRS has stated that from 2004 to 2013, Microsoft, $MSFT, underpaid its taxes by $28.9 billion.

Per CNBC: Microsoft plans to contest the notices through the IRS’ administrative appeal and is willing to go to judicial proceedings, if necessary.

“Microsoft disagrees with these proposed adjustments and will pursue an appeal within the IRS, a process expected to take several years,” the company said in its filing. “We believe we have always followed the IRS’s rules and paid the taxes we owe in the U.S. and around the world.”

Microsoft said that as of Sept. 30, 2023, it believes its allowances for income tax contingencies are adequate.