On August 11, 2021, the Tax Court issued a Memorandum Opinion in the case of Mohsen v. Commissioner (T.C. Memo. 2021-99). The primary issues presented in Mohsen v. Commissioner were whether the Tax Court possessed jurisdiction to decide the taxpayer’s claim for refund and whether the taxpayer’s unpaid income tax liability could be offset by a claimed (time-barred) credit. Filing Background to Mohsen v. Commissioner On April 15, 2002, the petitioner mailed the IRS a Form 4868 (Application for Automatic Extension of Time To File U.S. Individual Income Tax Return) for 2001. The petitioner attached to his Form 4868 a $43,000 check. The IRS applied this amount to pay petitioner’s tax liability for 2001, and the remainder was sent to excess collection. On or about August 25, 2003, the IRS prepared a substitute for return on behalf of the petitioner for 2001. On October 29, 2015, the petitioner untimely filed…