Business Tax Deadline, a partnership files in March

Form 1065 is the partnership return. For a year that follows the calendar, it is due on the 15th day of the third month. In 2026 that printed day is a Sunday, so the return moves to Monday 16 March.

Partners sometimes text each other the personal date and assume the company rides along. It does not. The company has its own row. The K-1s come out of that row, and the personal returns wait on them.

IRS Publication 509 is the table for the weekend rule. A due day that lands on a weekend moves to the next business day.

A Monday with February still open is a date and a guess. The bank has not agreed to February. Someone's draw is still sitting in the wrong account. The return can be assembled, and it will be wrong in a way that shows up on every K-1.

We close February first. That means the accounts agree, the draws are in the right place, and the number that will land on the K-1 is a number the partners can explain. Then the Monday is a filing day instead of a rumor.

The filing charge for a late partnership return is described on the IRS failure-to-file page as a per-partner amount. This page does not restate that amount. Paying late is a different charge from filing late. Both can be true at once.

We keep the books, set the payroll file up with the provider you already run, and prepare the partnership return from months that have closed. A signed opinion, if a lender wants one, belongs with a firm that holds that work. We do not represent you before the IRS.

The week of that Monday, the notice often sits on the kitchen table beside the bank page. We would rather open that page and show an open February than mail a K-1 the partners cannot explain. The Monday does not move because the table is crowded. The month under the Monday still has to close before the return leaves.