On July 31, 2015, the President signed the Surface Transportation and Veterans Health Care Choice Improvement Act of 2015 (the Highway Act) into law, providing a three-month extension of the general expenditure authority for the Highway Trust Fund (HTF). Part of the HTF extension was paid for by changes to tax compliance provisions, the most significant of which is a change to the longstanding due date for C corporation [Form 1120 (“U.S. Corporation Income Tax Return”)] and partnership [Form 1065 (“U.S. Return of Partnership Income”)] returns.

For tax years beginning after 2015, the Highway Act switches the Form 1120 and Form 1065 initial due dates. Thus, beginning with 2016 returns:

• The Form 1065 due date will be accelerated by a month to two and a half months after the close of the partnership’s tax year (March 15 for calendar-year partnerships). A six-month extension (through September 15 for calendar-year partnerships) will also be allowed.

• The Form 1120 due date will generally be deferred by a month to three and a half months after the close of the corporation’s tax year (April 15 for calendar-year corporations). However, under a special transition rule, for C corporations with fiscal years ending on June 30, the change won’t apply (it will continue to be September 15) until tax years beginning after 2025. An automatic six-month extension will generally be allowed. However, until 2026, an automatic five-month extension (to September 15) applies to calendar-year corporations and an automatic seven-month extension (to April 15) applies to June 30 fiscal year corporations.

Note that the filing deadline for S corporations has not changed. So, for years beginning after 2015, S corporations and partnerships will have the same March 15 filing deadlines. Also, for calendar-year entities, the revised deadlines will first apply to 2016 returns filed in 2017.