Letter 531: Statutory Notice of Deficiency (90-Day Letter)
The Statutory Notice of Deficiency, required by law, informs the taxpayer of the tax assessed, plus penalties and interest, that he or she owes. This letter also advises the taxpayer of the appeal rights to the U.S. Tax Court. [IRM 4.8.9.9.3 (7-9-2013)]
Updated: June 23, 2025