Can I change my company's accounting year-end date?

Yes. You can change your accounting reference date by notifying Companies House, subject to restrictions on how frequently you can shorten the year and maximum period limits. Your accountant can advise on whether a different year-end date would improve your tax planning position or simplify your cashflow cycle.

What happens if I miss the corporation tax payment deadline?

HMRC charges interest on late corporation tax from the due date. If the return is also filed late, a £100 penalty applies immediately, rising to £1,000 after three months. Penalties can be appealed on grounds of reasonable excuse, but cashflow difficulty alone is not generally accepted as a valid excuse.

How to Prepare Your Limited Company for Year-End

Reconcile all balance sheet accounts

The most time-consuming part of year-end preparation is reconciling balance sheet accounts to independent evidence. This means matching your bank balance to your bank statement, reconciling trade debtors to outstanding invoices, trade creditors to unpaid supplier invoices, and your VAT control account to your VAT returns.

Directors loans accounts — money you have drawn from or lent to the company outside of salary and dividends — need particular attention. Overdrawn directors loan accounts have corporation tax and potentially benefit-in-kind implications that your accountant will need to address.

Review fixed assets and stock

Carry out a physical check of fixed assets listed on your register. Write off any assets that have been disposed of or are no longer in use. If you hold stock, a physical stock count at or near the year-end date is required to support the stock figure in your accounts — a number plucked from a spreadsheet without physical verification will be challenged by your accountant and possibly by HMRC.

Consider whether any stock is obsolete or damaged and should be written down to net realisable value. Writing down slow-moving stock before year-end reduces your taxable profit legitimately.

Consider tax planning opportunities before the year-end date

Once your accounting year-end passes, most tax planning opportunities close. Review whether to accelerate capital expenditure before year-end to benefit from Annual Investment Allowance (AIA), whether to make pension contributions (which are deductible in the year paid, not accrued), and whether your director salary and dividend split is optimal for the current tax year.

Research and Development (R&D) tax credits must be claimed in the accounting period in which the expenditure falls. If your business undertakes qualifying R&D activity, alert your accountant before the year-end so costs are coded correctly throughout the year.

Gather supporting documents for your accountant

Preparing a clean handover pack for your accountant reduces their time and therefore your fee. As a minimum, provide: 12 months of bank statements for all company accounts, a complete list of sales invoices and purchase invoices, your payroll summary from your payroll provider, receipts for expenses claimed through the company, and any hire purchase or lease agreements entered into during the year.

If you use cloud accounting software (Xero, QuickBooks, Sage), ensure all transactions are categorised and reconciled before you hand over access. An uncategorised transaction pile is the single biggest cause of accountant time overruns at year-end.

Know your filing deadlines and penalties

UK limited companies must file accounts at Companies House within nine months of the accounting year-end. The corporation tax return (CT600) must be filed with HMRC within 12 months of the year-end. Corporation tax itself is due nine months and one day after the year-end for most companies.

Late filing penalties at Companies House start at £150 for accounts up to one month late and rise to £1,500 for accounts more than six months late. HMRC late filing and payment penalties are separate and can accumulate quickly. A diarised reminder two months before each deadline is the simplest safeguard.