You must file the annual report of earnings on or before the 15th day of the fourth month following the end of your taxable year. If you use a calendar year, your annual report of earnings is due April 15. We assume your taxable year is a calendar year until you show us that you have a different taxable year.
If the due date falls on a Saturday, Sunday, legal holiday, or other non-work day for Federal employees set by statute or Executive Order, it is extended to the first full work day after the original deadline.
Last Revised: March, 2001
Social Security Handbook