In your first year as a limited company, you will have two corporation tax returns to prepare and submit. This is because a Corporation Tax period can only be a maximum of 365 days. When you incorporate your business, the month in which you incorporate, becomes your year end in future years. So for example if you incorporate your business on the 9th September 2022, your year end date will be 30th September 2023. This means the first year will be longer than 365 days. You will be required to prepare a tax return for the period 9th September 2022-8th September 2023, and then a shorter corporation tax return for the period 9-30th September 2023. We usually apportion costs and income equally across these periods when preparing the corporation tax returns.