I have three dormant companies — what do I file?

By Ben Davies · Updated 5 October 2026

Three of everything. A dormant company is a separate legal person however many you own, so each one files its own returns on its own dates. Nothing is combined, and one company being up to date says nothing about the other two. Here is the whole list, then how to make it one job instead of three.

Per company, every year

The CT600 row is the one to check per company rather than assume. HMRC opens a Corporation Tax record for every new company, but a return is due only for a period it has sent a notice for. One company can get a notice every year while its sibling gets none. The free CT600 checker answers it company by company.

So the worst case is nine dated obligations a year, and the usual case is six plus whatever HMRC asks for.

Three of each credential

Each company has its own Companies House authentication code, its own 10-digit UTR, and its own Government Gateway (HMRC login) enrolment for Corporation Tax. An enrolment is tied to one company, so a CT600 has to go in through the login enrolled for that company's UTR — submitting company B's return under company A's login is a classic HMRC rejection for people with several companies. Keep a note of which code and login belongs to which company.

Does one company's status affect the others?

No. Each company is judged on its own transactions, so one having a bank account that earns interest doesn't stop the other two being dormant. The one way they interact is money moving between them: a loan from one to another puts a transaction in both companies' books, and both lose dormancy for the year. Keep them financially sealed from each other — each pays its own confirmation statement fee, or you pay it personally and don't take the money back — and they stay dormant under section 1169 indefinitely.

Two things happen once, not three times. Under ECCTA you verify your identity once and it is reused across every company you're a director of. And for the small profits rate, a company that carried on no trade or business in the period isn't counted as an associated company, so dormant siblings don't dilute a trading company's thresholds.

Making three companies one job

• Line up the year ends — or deliberately don't. Three companies with three different accounting reference dates means deadlines scattered through the year. You can change a company's year end (shorten it as often as you like; extend it once in five years, to at most 18 months) so all three share one date and you do the filings in a single sitting. Some owners prefer them spread out. Either is fine, as long as it is chosen rather than accidental.
• One dashboard. DormantFile's Multiple plan holds up to ten companies for £39 a year — the same £39 whether you have two or ten; the Agent plan takes it to 100. Every company is shown sorted by whichever deadline is nearest, and the dormant accounts and any nil CT600 are filed for each from the same place, with reminders grouped across all of them rather than three separate streams. The confirmation statements stay with you, and we remind you when each is due. Enter each company's accounting period as its HMRC notice turns up and we remind you about any Corporation Tax deadline you add as well — three notices, three periods, and the reminders still come grouped.
• One calendar feed. Every deadline for every company in a single subscription in Google, Outlook or Apple Calendar.
• Autopilot per company. Once a company has filed with us, next year's dormant accounts can be prepared automatically and sent to you for one-click confirmation before the deadline — three companies, three clicks a year.
• A register watch on each. Every company you add is checked daily for changes you didn't make to its directors, address, owners or name, and for strike-off notices, which matters more with three unwatched companies to hijack than with one.

Before you add them, run each company number through the free Companies House audit. It shows overdue filings and strike-off risk per company in a few seconds, and it is the quickest way to find out whether one of the three is already behind.

The specific cases: is my property SPV a dormant company? · what does a holding company with dormant subsidiaries have to file? · what do I have to file for companies registered just to protect a name?

Read the full guide: Managing multiple dormant companies