Corporation Due Date 2024. If your financial year ends on 31 may 2024, you’ll need to: With an extension, the deadline for filing is september 15.

For example, if a corporation operates on a calendar year, the due date for its form 1120 would be april 15, 2024, for the 2023 tax year. C corporations, s corporations, partnerships, and sole proprietorships all have specific federal income tax return due dates.