The IRS mailed its notice of determination to an incorrect address. On October 17, 2016, U.S. Tax Court held in favor of the taxpayer who claimed that he was deprived of the statutory notice. Section 6213(a) of the Internal Revenue code states a notice of deficiency should be duly mailed to the taxpayer’s last known address before a deficiency may be assessed. If the IRS hasn’t mailed a notice of deficiency, no collection of an assessment of the deficiency may proceed. Tax Court Memo 2016-191.