Section 4. Taxable years to which tax applies; tax for taxable years beginning prior to and ending after July first, nineteen hundred sixty-six

--  (a)  General.--The  tax  imposed  by section two, with any
  modification permitted by subdivision (b) of this  section,  is  imposed
  for  each  taxable  year  beginning with taxable years ending after July
  first, nineteen hundred sixty-six and prior to January  first,  nineteen
  hundred  seventy-six and each taxable year beginning in nineteen hundred
  seventy-five and ending in nineteen hundred seventy-six.
    (b) Alternate methods for determining tax for taxable years ending  on
  or  after  July  first, nineteen hundred sixty-six and on or before June
  thirtieth, nineteen hundred sixty-seven. -- (1) The tax for any  taxable
  year ending on or after July first, nineteen hundred sixty-six and on or
  before  June  thirtieth,  nineteen hundred sixty-seven shall be the same
  part of the tax which would have been imposed had section  two  been  in
  effect  for  the  entire  taxable year as the number of months (or major
  portions thereof) of  the  taxable  year  occurring  after  July  first,
  nineteen hundred sixty-six is of the number of months (or major portions
  thereof)  in  the  taxable  year. The credit allowed against such tax as
  provided by section twenty shall be reduced by a fraction the  numerator
  of which is equal to the number of months (or major portions thereof) in
  such  taxable  year  which  occurred before July first, nineteen hundred
  sixty-six and the denominator of which is equal to the number of  months
  (or major portions thereof) in such taxable year.
    (2)  In  lieu  of  the  method  of  computation  of  tax prescribed in
  paragraph (1), if  the  taxpayer  maintains  adequate  records  for  any
  taxable  year  ending on or after July first, nineteen hundred sixty-six
  and on or before June thirtieth, nineteen hundred sixty-seven,  the  tax
  for  such taxable year, at the election of the taxpayer, may be computed
  on the basis of the city taxable income which the  taxpayer  would  have
  reported  had  he  filed  a  return  under this local law for the period
  (referred to in this paragraph as "short period") beginning July  first,
  nineteen  hundred  sixty-six  and  ending  with  the  last  day  of  the
  taxpayer's taxable year. If a return for a period of  less  than  twelve
  months  is  made  under  this paragraph (2), the city taxable income for
  such short period shall be placed on an annual basis by multiplying such
  income by twelve and dividing the result by the number of months in  the
  short  period.  In  determining city taxable income under this paragraph
  (2), the city personal exemptions provided by section sixteen, shall  be
  reduced  to  amounts that bear the same ratio to the full exemptions, as
  the number of months in the short period bears  to  twelve.  The  credit
  allowed  against such tax as provided by section twenty shall be reduced
  by a fraction the numerator of which is equal to the  number  of  months
  (or  major  portions thereof) in such taxable year which occurred before
  July first, nineteen hundred sixty-six and the denominator of  which  is
  equal  to  the  number  of  months  (or  major portions thereof) in such
  taxable year. The tax shall be the same part of the tax computed on  the
  annual  basis  as  the number of months in the short period is of twelve
  months.  Except as provided in this paragraph  (2),  the  tax  for  such
  period ending on or before June thirtieth, nineteen hundred sixty-seven,
  shall  be computed in accordance with the other provisions of this local
  law.