Example. H & W marry on September 25, 2001. H is on a fiscal year ending June 30, and W is on a calendar year. H wishes to change to a calendar year in order to file joint returns with W. W's first taxable year after marriage ends on December 31, 2001. H may not change to a calendar year for 2001 since, under this paragraph (d), he would have had to file a return for the short period from July 1 to December 31, 2000, by April 16, 2001. Since the date of marriage occurred subsequent to this due date, the return could not be filed under this paragraph (d). Therefore, H cannot change to a calendar year for 2001. However, H may change to a calendar year for 2002 by filing a return under this paragraph (d) by April 15, 2002, for the short period from July 1 to December 31, 2001. If H files such a return, H and W may file a joint return for calendar year 2002 (which is W's second taxable year ending after the date of marriage).
26 C.F.R. §1.442-1