Dormant Company Filing: Companies House and HMRC

A dormant company is one that has had no significant accounting transactions in the year. Many one-person companies sit dormant for a while — between contracts, after pivoting, or while the founder works elsewhere. Filing requirements still apply, but they're much lighter.

Two dormant statuses (don't confuse them)

There are two separate definitions of dormant — one for Companies House and one for HMRC.

Dormant for Companies House

A company is dormant if it has had no significant accounting transactions during the period. The following don't count as transactions:

• Filing fees paid to Companies House.
• Penalties paid to Companies House.
• Money paid for shares when the company was first incorporated.

Anything else — bank fees, expenses, a single sale — breaks dormant status.

Dormant for HMRC

A company is dormant for Corporation Tax if it isn't carrying on a business, isn't trading, and has no other taxable income (interest, gains, etc.).

You can be dormant for one and not the other — for example, a company earning a tiny amount of bank interest is dormant for Companies House but not for HMRC.

What to file at Companies House

If dormant, you can file the simplified AA02 dormant company accounts form via WebFiling. It's free, takes a few minutes, and the public record just shows minimal balance-sheet information.

You also still need to:

• File a confirmation statement (CS01) annually — £34 (online).
• Keep your registered office and director details up to date.

What to file at HMRC

1. Tell HMRC the company is dormant. Sign in to HMRC online or write to your Corporation Tax office. HMRC will usually stop sending CT600 notices.
2. No CT600 required while dormant — provided HMRC has acknowledged the dormant status.
3. If HMRC sends a CT600 notice anyway, you must file it. A nil return is fine — enter zeros throughout and submit.

Becoming dormant after trading

• File a final CT600 covering the period up to the last trading date.
• Pay any tax owed.
• Notify HMRC the company is now dormant.
• Continue Companies House filings (AA02 + CS01).

Coming out of dormancy

When the company starts trading again:

1. Tell HMRC within 3 months that the company is now active.
2. HMRC issues a new accounting period and CT600 notice.
3. Companies House filings switch back to micro/small accounts.

Should I keep a dormant company alive?

Pros: keeps the name and registration. Cons: small annual cost (CS01 fee) and admin overhead. If you have no plans to use the company within a year or two, see Closing or Selling a UK Limited Company.

Summary

Dormant filings are light: AA02 + CS01 at Companies House, and a one-time notification to HMRC. Just don't ignore them — Companies House late-filing penalties still apply, even on dormant accounts.