For UK limited companies

Your books, and the tax return that comes out of them.

Stewardry keeps the accounts and files the corporation tax return — CT600, computations and accounts — straight to HMRC. One ledger, one set of figures, no re-keying at the year end.

In testing with HMRC's Software Developers Support Team under vendor ID 9633. Not yet open to the public.

Worked example Year ended 31 March 2025
A corporation tax computation from accounting profit to tax payable
Turnover 250,000.00
Trading costs (150,000.00)
Depreciation (12,000.00)
Profit per accounts 88,000.00
Add back: depreciation 12,000.00
Add back: client entertaining 3,000.00
Less: capital allowances (30,000.00)
Trading profit 70,000.00
Bank interest 2,000.00
Profits chargeable 72,000.00
Corporation tax at 25% 18,000.00
Marginal relief (2,670.00)
Tax payable 15,330.00

The problem

Most small companies keep their books twice.

Once in the bookkeeping software, and again in whatever the accountant uses to prepare the return. The figures are copied across, adjusted by hand, and reconciled at the year end — which is where the cost sits, and where the errors get in.

Stewardry closes that gap. The return is computed from the same ledger the invoices went into, so the accounts you file are the accounts you kept.


How it works

Three steps, one set of figures.

  1. 01

    Keep the books

    Invoices, bills, bank transactions and the ledger behind them. The ordinary work of running a company, done in one place.

  2. 02

    Review the computation

    Stewardry proposes which costs tax disallows and what qualifies for capital allowances. It asks you to confirm anything it inferred, and refuses to file until you have.

  3. 03

    File to HMRC

    The CT600, the computations and the accounts go to HMRC as one submission, tagged in iXBRL. You keep the receipt.


What it does not do

It will not file a return you have not read.

Deciding whether a cost is deductible is judgement, not lookup. Where Stewardry has inferred something that changes the tax — whether a payment was entertaining, whether income belongs to the trade — it says so and asks a person to confirm it. Filing is refused until someone has.

A tax return is a declaration a director signs. Software should make it easier to get right, not easier to send without looking.


Questions

Reasonable things to ask.

Who is this for?
Directors of small UK limited companies who would rather not keep two systems, and the accountants who file on their behalf.
Do I still need an accountant?
Most companies should have one. Stewardry does the arithmetic and the filing; it does not give advice, and it is built to be reviewed rather than trusted blindly.
What if you disappear?
The accounting platform is open source under the AGPL. You can host it yourself, and the source is public. That is a deliberate answer to a fair question about a small supplier.
Is my data in the UK?
Yes. Stewardry runs on infrastructure in the United Kingdom, and your ledger is not shared with anyone.

Early access

We are looking for a handful of companies to file with first.

If you run a small limited company, or file for people who do, we would like to hear from you before we open more widely.

hello@stewardry.co.uk