Corporate Tax Return Extension Due Date 2024. Partnerships and s corporations must apply for an extension by march 15, 2024. Tax deadlines vary for startups and other businesses classified as corporations.
You must file it by the original due date of the return. You can extend the due date for filing your personal income tax return by six months (e.g., to october 15, 2024, for 2023 tax year returns) by filing form 4868 or.