Dormant and nil CT600

Dormant company and nil CT600 filing: what to check before assuming no return is needed.

Dormant companies, nil Corporation Tax returns, and companies with no tax to pay are often confused. This guide separates the HMRC filing question from Companies House accounts and the CT600 review workflow.

Dormant for Corporation Tax is an HMRC status, not a shortcut

A company that has stopped trading and has no other income may be dormant for Corporation Tax. GOV.UK says a company can tell HMRC it is dormant, and after HMRC is told it will not normally have to file another Company Tax Return unless HMRC asks for one or the company begins trading again.

The important word is "normally". If HMRC has issued a notice to deliver a Company Tax Return, the company should not simply ignore it because the accounts look quiet. The filing decision should be based on the HMRC position, the company's activity, and whether a return has been requested.

Dormant does not mean Companies House disappears

Corporation Tax dormancy is separate from Companies House filing. A dormant company may still need to send information to Companies House, such as dormant accounts and confirmation statements. The old joint HMRC and Companies House filing service closed on 31 March 2026, so directors should be especially careful not to assume one online step covers both regimes.

Nil CT600 is not the same as dormant

A nil CT600 usually means a Company Tax Return is being filed but the Corporation Tax payable is nil. That can happen because of losses, allowances, reliefs, or a very small amount of activity. It is not the same as telling HMRC the company is dormant.

A company can have no Corporation Tax to pay and still need a CT600. The review question is not only "is tax payable?" It is "does HMRC require a return and what facts need to be disclosed?"

When a quiet company still needs review

  • The company traded for part of the year and then stopped.
  • The company has bank interest, investment income, or other non-trading income.
  • Expenses were incurred before trade began or after trade ceased.
  • There are losses to carry forward or claim.
  • Capital allowances, disposals, or balancing adjustments exist.
  • A director's loan account is overdrawn even though trading profit is nil.
  • HMRC has issued a notice to deliver a Company Tax Return.

Practical workflow for accountants

Accountancy practices should treat dormant and nil cases as low-fee but not no-control. A short checklist protects the practice and makes the client conversation clearer.

  • Check whether HMRC has asked for a Company Tax Return for the period.
  • Confirm the trading status and whether the company had any income.
  • Separate HMRC Corporation Tax dormancy from Companies House filing duties.
  • Check bank statements and accounts movements for interest, expenses, loans, and asset activity.
  • Record why a nil CT600 is being filed or why no CT600 is expected.
  • Keep evidence of HMRC dormancy notifications or client instructions.

Practical workflow for directors

Directors should avoid waiting until the deadline to decide whether the company is dormant. The safer route is to collect the source facts, check HMRC correspondence, and decide whether the company needs a CT600, a dormancy notification, Companies House filings, or some combination.

If the company has never traded, recently stopped trading, or has no tax to pay, that is still worth documenting. A clean record today prevents confusion when a future year restarts trading or when an accountant takes over the file.

How Robocount treats dormant and nil cases

Robocount is designed to make CT600 review decisions explicit. For a dormant or nil case, that means keeping the HMRC filing requirement, company activity, accounts position, and return outcome visible in one workflow.

  • Supports CT600 preparation where HMRC requires a return even if tax payable is nil.
  • Prompts review of losses, allowances, loan accounts, and supplementary-page triggers.
  • Helps practices keep a clear note of why a return is nil or why a case is treated as dormant.
  • Separates Corporation Tax return workflow from Companies House obligations.
  • Gives AI and API-led workflows structured status checks instead of a vague "inactive company" label.

FAQ

Do dormant companies need to file a CT600?

GOV.UK says that after HMRC has been told a company is dormant, the company will not have to file another Company Tax Return unless HMRC asks it to or the company begins trading again. If HMRC has issued a notice, check the specific position before ignoring it.

Is a nil CT600 the same as telling HMRC the company is dormant?

No. A nil CT600 is a return with no Corporation Tax payable. Dormancy is a status for Corporation Tax purposes where the company is not trading and has no other income.

Do dormant companies still file accounts?

Dormant companies can still have Companies House filing obligations. HMRC Corporation Tax dormancy does not remove Companies House requirements.

Can Robocount file a nil CT600?

Robocount is built for CT600 preparation, review, and filing workflows. A nil return still needs discipline around period dates, source figures, attachments, approval, and HMRC submission evidence.

Useful official references

This guide is general product and filing workflow information, not tax advice. Check current GOV.UK guidance, HMRC notices, and the company's activity before deciding whether to file.