As a result of a federal holiday, taxpayers have until Monday, April 18, this year to file individual and calendar-year fiduciary income tax returns. As a reminder, an extension of time to file a return does not extend the due date for payment of any tax owed, so don’t procrastinate if you think you might owe tax! The IRS and South Carolina will charge a 0.5% per month penalty (plus interest) for any 2016 tax not paid by April 18.