Extending the accounting period of a new company: who is entitled and how to do it

Have you started a business and your company was established in the last 3 months of the year? Postpone your first corporation tax return until next year! We will tell you how to proceed.

Who can extend their accounting period?

If your company was established between 1 October and 31 December, you can apply to the tax office for an extension of your first accounting period. This way, you don't have to prepare your tax return in a few weeks or months, but can file it over a longer period of time (up to 15 months). This option applies only to legal entities that keep accounts, not to self-employed persons.

What are the rules?

• A company is formed by registration in the commercial register. If the incorporation took place between 1 October and 31 December, you can take advantage of the longer accounting period, which will last until the end of the year following incorporation.
• The resulting length of the accounting period then depends on the date of establishment of the company. For example, if it was established on November 1, 2025, the extended accounting period will last from November 1, 2025, to December 31, 2026 (a total of 14 months). You will therefore file your first tax return in the spring of 2027.

The extension of the accounting period is allowed by Section 3, paragrapf 4 a) of Act No. 563/1991 Coll. on Accounting and is beneficial for your financial planning. You will thus get rid of the hassle of tax administration this year, reduce the costs of accounting work and postpone the date of payment of any tax liability, which will come in handy in the early stages of business.

How to extend the accounting period of a new company?

The obligation to notify the extension of the accounting period for newly established entities is not directly regulated by law. In our experience, it is advisable to inform the tax office of the extension.

You need a company data box through which you can send the tax office a notification of the extension no later than the date on which you would normally file your corporate income tax return. Companies submit this electronically within four months of the end of the calendar year – the official deadline in 2026 is May 2.

We will deal with the notice for you

If you're interested in extending your accounting period and are interested in deferring your tax return, but you're not sure how to notify the tax office, contact us using the form below - we'll be happy to help.