Corporation Tax & Annual Accounts

Yes, in most cases. If your company is active and registered for Corporation Tax, you’ll need to file a CT600 even if you had no income or made a loss. There’s an upside: reporting a loss lets you carry it forward and offset it against future profits, which can reduce your tax bill when things pick up.

No – the CT600 is only for UK limited companies. Sole traders report business income through Self Assessment. Partnerships file a Partnership Tax Return (SA800). If you’re unsure which applies to your business structure, we can point you in the right direction.

Yes – and we’d recommend it. Filing both at the same time, using the same figures, keeps everything consistent and reduces the risk of errors. We offer a combined filing service that covers both.

You can amend your CT600 up to 12 months after the original filing deadline. We can help you prepare and resubmit a corrected return. The sooner you flag it, the better – HMRC treats unprompted corrections more favourably than ones they had to prompt.

A few weeks, typically – though it can vary. Once processed, your Corporation Tax account will be updated. If you’re due a repayment, HMRC aims to process refunds within 25 working days, though this can sometimes take longer.

Sometimes, yes – particularly for dormant companies, where HMRC may accept a simplified filing. For active companies, HMRC generally expects full accounts and computations alongside the CT600. We’ll let you know what’s needed based on your situation.

It’s the reference that makes sure your payment gets matched to the right accounting period. It’s made up of your 10-digit UTR, the letter “A”, and a 6-digit accounting period end date (in DDMMYY format). You can find it in your HMRC online account or on correspondence from HMRC. Worth double-checking before you pay – a wrong reference can lead to a misallocated payment.

If your company has lent money to a director or shareholder, that loan may attract a tax charge under section 455 of the Corporation Tax Act 2010. It’s reported on the supplementary CT600A form, and the charge is 33.75% of any outstanding balance at the end of the accounting period. The charge is repayable to your company 9 months after the end of the accounting period in which the loan is repaid or written off. We can help you complete the CT600A and work out any amount due.

You can shorten your accounting period at any time without approval. Extending it is more restricted – generally only once every 5 years, and you’d need to act within the first 6 months of the period you want to extend. HMRC doesn’t need to sign off the change, but you’ll need to notify Companies House. We can help you file correctly for non-standard periods.

If you miss the filing deadline, HMRC can issue a determination – their estimate of what you owe. It becomes legally due and payable, and you can’t appeal it. The only way to get rid of it is to file your actual return. If you’ve received one, filing quickly is the priority. We can help you get that done.

A company being wound up or in administration still has Corporation Tax obligations. The liquidator or administrator is responsible for making sure returns get filed for the relevant periods. We can work with you or your insolvency practitioner to prepare and submit any outstanding CT600s.

Yes. Since August 2023, all R&D tax relief claims – under both the SME scheme and RDEC – must be accompanied by an Additional Information Form (AIF) submitted through HMRC’s online service before the CT600 is filed. Skip the AIF and HMRC will disallow the R&D claim. We can make sure your claim is properly documented and submitted in the right order.