File the 2012 return for calendar year 2012 and fiscal years beginning in 2012 and ending in 2013. If the return is for a fiscal year or a short tax year (less than 12 months), fill in the tax year space at the top of the form.
The 2012 Form 1041 may also be used for a tax year beginning in 2013 if:
The estate or trust has a tax year of less than 12 months that begins and ends in 2013, and
The 2013 Form 1041 is not available by the time the estate or trust is required to file its tax return. However, the estate or trust must show its 2013 tax year on the 2012 Form 1041 and incorporate any tax law changes that are effective for tax years beginning after December 31, 2012.