Filing obligations for private limited companies

Those responsible for the accounts and tax compliance of private limited companies must ensure they are fully aware of the relevant obligations and statutory deadlines.

Following the end of each financial year, a private limited company is required to prepare full annual accounts and submit a Company Tax Return. The deadline for filing the first set of accounts must be filed with Companies House within 21 months of the date of incorporation. Thereafter, annual accounts must be filed within 9 months of the end of each financial year.

Corporation Tax is payable 9 months and 1 day after the end of the relevant accounting period. As a result, the tax liability will typically fall due before the filing deadline for the Company Tax Return.

In most cases, the Company Tax Return must be submitted within 12 months of the end of the accounting period. Filing is required to be completed online in iXBRL format, using either HMRC’s own software or approved third-party software.

The Corporation Tax accounting period will generally correspond with the 12-month company financial year covered by the annual accounts.

Penalties may be imposed by both Companies House and HMRC for late filing or non-compliance, and it is therefore essential that all deadlines are carefully monitored and adhered to.

Source:Companies House | 13-04-2026
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Aitch
Aitch is the visionary founder and CEO of CIGMA Accounting Ltd, a boutique accounting and tax advisory firm with offices in Wimbledon and Farringdon, London. With over a decade of experience, Aitch has built a reputation for strategic tax planning, complex HMRC compliance resolution, and innovative AI-powered accounting workflows that help SMEs, landlords, and high-net-worth clients streamline their finances. His expertise spans corporation tax, inheritance tax planning, R&D tax credit claims, capital allowances, and international tax matters, making him a trusted advisor for clients seeking to minimise tax liabilities while staying fully compliant. Aitch is passionate about bridging traditional accounting principles with cutting-edge digital solutions, allowing businesses to operate efficiently and future-proof their financial systems. Through CIGMA, he aims to make accounting smarter, faster, and more human-centric - empowering clients to focus on growth while staying ahead of regulatory changes.