Section 11-644. Declarations of estimated tax

(a)  Requirements  of
  declaration.  Every taxpayer subject to the tax imposed  by  subdivision
  (a)  of  section  11-639  of  this  part shall make a declaration of its
  estimated tax for the current taxable year, containing such  information
  as   the  commissioner  of  finance  may  prescribe  by  regulations  or
  instructions, if such estimated tax can reasonably be expected to exceed
  one thousand dollars.
    (b) Definition of estimated tax. The term "estimated  tax"  means  the
  amount  which  a taxpayer estimates to be the tax imposed by subdivision
  (a) of section 11-639 of this part for the current  taxable  year,  less
  the  amount  which  it  estimates to be the sum of any credits allowable
  against the tax.
    (c) Time for filing declaration. A declaration of estimated tax  shall
  be  filed on or before June fifteenth of the current taxable year in the
  case of a taxpayer which reports on the basis of a calendar year, except
  that if the requirements of subdivision (a) of this  section  are  first
  met:
    (1)  after May thirty-first and before September first of such current
  taxable year, the declaration shall be  filed  on  or  before  September
  fifteenth, or
    (2)  after  August  thirty-first  and  before  December  first of such
  current taxable year, the  declaration  shall  be  filed  on  or  before
  December fifteenth.
    (d)  Amendments  of  declaration.  A  taxpayer may amend a declaration
  under regulations of the commissioner of finance.
    (e) Return as declaration. If, on or before February fifteenth of  the
  succeeding  year  in  the  case  of  a  taxpayer whose taxable year is a
  calendar year, a taxpayer files its return for the year  for  which  the
  declaration  is required, and pays therewith the balance, if any, of the
  full amount of the tax shown to be due on the return:
    (1)  such  return  shall  be  considered  as  its  declaration  if  no
  declaration  was  required to be filed during the taxable year for which
  the tax was imposed, but is otherwise required to be filed on or  before
  December  fifteenth pursuant to paragraph two of subdivision (c) of this
  section, and
    (2) such return shall be considered  as  the  amendment  permitted  by
  subdivision  (d)  of  this  section  to  be  filed on or before December
  fifteenth if the tax shown on the return is greater than  the  estimated
  tax shown on a declaration previously made.
    (f)  Fiscal  year. This section shall apply to taxable years of twelve
  months other than a calendar year by the substitutions of the months  of
  such fiscal year for the corresponding months specified in this section.
    (g)  Short  taxable  period.  If the taxable period for which a tax is
  imposed by subdivision (a) of section 11-639 of this part is  less  than
  twelve  months,  every  taxpayer  required  to  make  a  declaration  of
  estimated tax for such taxable period shall make such a  declaration  in
  accordance with regulations of the commissioner of finance.
    (h)  Extension  of  time.  The  commissioner  of  finance  may grant a
  reasonable extension of time, not to exceed three months, for the filing
  of any declaration required pursuant to this section, on such terms  and
  conditions as the commissioner may require.