In Pakistan financial year begins on 1st day of July of every calendar year and ends on 30th day of June of every calendar year . Foreign companies / multinational companies which follow other period are required to get permission from concerned Commissioner Inland Revenue to follow financial / accounting period with different dates.
Around ninety percent (90%) companies follow tradition financial year ( 1st July- 30th June), for this class of companies tax filing date is 31st day of December of each year.
Mostly foreign companies and subsidiaries of foreign companies follow different accounting period for the company whose accounting year ends between July and December , last date of filing of company tax return will be 30th day of on next year.
Suppose accounting year of a company is January 2017 to December 2017 such company will file company tax return on or before September 30, 2018.
Sub Section 2 of Section 118 of Income Tax Ordinance 2001, lays down the following
“A return of income 5[under section 114 or a statement under sub-section (4) of section 115] of a company shall be furnished —
(a) in the case of a company with a tax year ending any time between the first day of January and the thirtieth day of June, on or before the thirty-first day of December next following the end of the tax year to which the return relates; or
(b) in any other case, on or before the thirtieth day of September next following the end of the tax year to which the return relates.”
See also Corporate Tax Return