Under Income Tax Act, all proprietors below the age of 60 years are required to file income tax return if total income exceeds Rs. 2.5 lakhs. In the case of proprietors over the age of 60 years but below 80 years, income tax filing is mandatory if total income exceeds Rs.3 lakhs. Proprietors over the age of 80 years and above are required to file income tax return if the total income exceeds Rs.5 lakhs.
Also, only if the proprietor files income tax return before the deadline, losses if any in the business would be allowed to be carried forward. Also, the deduction under sections 10A, 10B, 80-IA, 80-IAB, 80-IB and 80-IC cannot be allowed unless the proprietorship income tax return has been filed on or before the due date.
For the assessment year 2017-18 only, which relates to income earned in Financial Year 2016- 17, proprietorship firms would be required to file Form ITR-3 or Form ITR-4-Sugam.
Form ITR-3 can be filed by a proprietor or a Hindu Undivided Family who is carrying out a proprietary business or profession.
Form ITR-4-Sugam can be filed by a proprietor who would like to pay income tax under the presumptive taxation scheme. Presumptive taxation scheme is designed to help ease the compliance burden of small businesses by assuming a set profit margin on the total income of the business or profession.