Section 11-673. Assessment

1.  Assessment date. The amount of tax which a
  return shows to be due, or the amount of tax which a return  would  have
  shown  to  be  due  but  for a mathematical error, shall be deemed to be
  assessed on the date of filing of  the  return  (including  any  amended
  return  showing  an increase of tax). If a notice of deficiency has been
  mailed, the amount of the deficiency shall be deemed to be  assessed  on
  the  date  specified  in  subdivision  two  of  section  11-672  of this
  subchapter if no petition is both served on the commissioner of  finance
  and  filed  with the tax appeals tribunal, or if a petition is so served
  and filed, then upon the  date  when  a  decision  of  the  tax  appeals
  tribunal  establishing  the amount of the deficiency becomes final. If a
  report or an amended return filed pursuant to subchapter two or three of
  this chapter concedes the accuracy  of  a  federal  or  New  York  state
  adjustment  or  change  or correction or renegotiation or computation or
  recomputation of tax, any deficiency in  tax  under  subchapter  two  or
  three of this chapter resulting therefrom shall be deemed to be assessed
  on the date of filing such report or amended return, and such assessment
  shall be timely notwithstanding section 11-674 of this chapter.
    If  a report filed pursuant to subchapter two of this chapter concedes
  the accuracy of a state change or correction of sales  and  compensating
  use  tax  liability,  any deficiency in tax under subchapter two of this
  chapter resulting therefrom shall be deemed  assessed  on  the  date  of
  filing  such report, and such assessment shall be timely notwithstanding
  section 11-674 of this chapter.
    If a notice of additional tax due, as prescribed in  subdivision  five
  of  section  11-672  of this chapter, has been mailed, the amount of the
  deficiency shall be deemed to be assessed on the date specified in  such
  subdivision unless within thirty days after the mailing of such notice a
  report  of  the  federal  or  New  York  state  adjustment  or change or
  correction or renegotiation or computation or recomputation of  tax,  or
  an  amended  return, where such return was required by subchapter two or
  three of this chapter, is  filed  accompanied  by  a  statement  showing
  wherein  such federal or New York state determination and such notice of
  additional tax due are erroneous.
    If a notice of additional tax due, as prescribed in  subdivision  nine
  of section 11-672 of this subchapter, has been mailed, the amount of the
  deficiency  shall be deemed to be assessed on the date specified in such
  subdivision unless within thirty days after the mailing of such notice a
  report of the state change or correction, or a copy of an amended return
  or report, where such copy  was  required  by  subchapter  two  of  this
  chapter,  is filed accompanied by a statement showing wherein such state
  determination and such notice of additional tax due are erroneous.
    Any amount paid as a tax or in respect of a tax,  other  than  amounts
  paid  as  estimated tax, shall be deemed to be assessed upon the date of
  receipt of payment notwithstanding any other provisions.
    2. Other assessment powers. If the mode or time for the assessment  of
  any  tax  under  the named subchapters (including interest, additions to
  tax and  assessable  penalties)  is  not  otherwise  provided  for,  the
  commissioner of finance may establish the same by regulations.
    3.  Estimated  tax. No unpaid amount of estimated tax under subchapter
  two or three of this chapter shall be assessed.
    4. Supplemental assessment. The commissioner of finance  may,  at  any
  time  within  the  period  described for assessment, make a supplemental
  assessment,  subject  to  the  provisions  of  section  11-672  of  this
  subchapter  where  applicable,  whenever  it  is  ascertained  that  any
  assessment is imperfect or incomplete in any material respect.
    5. Cross reference. For assessment in case of  jeopardy,  see  section
  11-685 of this subchapter.