- Companies
- Property developers
- London
- Summix Limited
Summix Limited
- Company number
- 05960166
- Incorporated
- 9 Oct 200620 years trading
- Registered office
- Fifth Floor, Berkeley Square House, Berkeley Square, London, W1J 6BY
- Nature of business
- Development of building projects
Summix Limited is a 20-year-old private limited company registered in London, company number 05960166, one of 14,100 property development companies in London. Its next accounts are due at Companies House on 30 December 2026, and its first CT600 is due at HMRC on 31 December 2026.
Key dates
Worked out from the year end and filing history on the Companies House register.
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Finances
From each year's balance sheet filed at Companies House. Small companies do not have to publish turnover or profit, so these are balance sheet figures.
- Net assets down £36K (-0.3%) on the year before, to £14M.
- Net assets rose in 1 of 5 year-on-year comparisons on record.
- 2 employees on average during the year.
- Balance sheets on record for 8 years, 2017 to 2024.
Net assets by year
| Year end | Net assets | Cash | Current assets | Owed within a year | Employees |
|---|---|---|---|---|---|
| 31 Dec 2024 | £14M | £935K | £41M | 2 | |
| 31 Dec 2023 | £14M | £5,330 | £38M | 2 | |
| 31 Dec 2022 | £14M | £456K | £38M | 2 | |
| 31 Dec 2021 | £13M | £617K | £50M | £42M | 2 |
| 31 Dec 2020 | £14M | £2M | £51M | £42M | 2 |
| 31 Dec 2019 | £14M | £484K | £52M | £43M | 2 |
| 31 Dec 2018 | £179K | £53M | £53M | ||
| 31 Dec 2017 | £74K | £45M | £44M |
Where Summix Limited is registered
The registered office is in London (W1J), in the Westminster local authority area, London. Show W1J 6BY on a map.
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Shared registered office
27 companies on our pages use this registered office address. An address shared this widely is usually an accountant's office or a company formation agent's service address, not where the business trades from.
What happens if Summix Limited files late
Companies House charges an automatic penalty the day after the deadline, and it rises the longer the accounts are late. These are the dates for this company's accounts due on 30 December 2026.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 31 Dec 2026 to 30 Jan 2027 | £150 |
| 1 to 3 months late | 31 Jan 2027 to 30 Mar 2027 | £375 |
| 3 to 6 months late | 31 Mar 2027 to 30 Jun 2027 | £750 |
| More than 6 months late | From 1 Jul 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 31 Mar 2027 | £200 |
| 3 months late | 30 Jun 2027 | another £200 |
| 6 months late | 30 Sep 2027 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 30 Mar 2028 | another 10% of any unpaid tax |
For returns filed on or after 1 April 2026. Late three times in a row and the £200 penalties become £1,000 each.
Company details
As held on the Companies House register.
- Company number
- 05960166
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 9 October 2006 (20 years ago)
- Registered office
- Fifth Floor, Berkeley Square House, Berkeley Square, London, W1J 6BY
- Nature of business
- Development of building projects (SIC 41100)
- Year end
- 30 December (accounting reference date)
- Accounts type
- Total exemption (full)
- Last accounts made up to
- 31 December 2024
- Last confirmation statement
- 9 October 2025
- Charges (mortgages)
- 1 outstanding of 3 registered
Filing notes for property development companies
Many property development companies are single-project vehicles. Stock of land and buildings sits on the balance sheet as work in progress until sale, and a company that has finished its project may become dormant rather than close.
Similar companies in London
Other active property development companies registered in London.
- Summix MDB Developments Limited2018
- Summix Mqe Developments Limited2023
- Summix NCL Developments Limited2017
- Summix Ocs Developments Limited2024
- Summix Planning Limited2020
- Summix RGB Developments Limited2016
- Summix Rle Developments Limited2019
- Summix RLT Developments Limited2016
All property development companies in London · All trades in London · Property developers across the UK
Frequently asked questions
When are Summix Limited's accounts due?
Summix Limited's next accounts are due at Companies House by 30 December 2026 (in 78 days), covering the period to 30 March 2026.
When is Summix Limited's CT600 due?
The first accounts cover more than 12 months, so there are two Company Tax Returns: one for the 12 months to 31 December 2025, due by 31 December 2026, and one for the period to 30 March 2026, due by 30 March 2027. Corporation tax is payable 9 months and 1 day after the end of each.
Is Summix Limited still trading?
Summix Limited is listed as active on the Companies House register as of 1 Oct 2026. Active means it has not been dissolved or entered insolvency; it does not show whether it is currently taking on work.
What does Summix Limited do?
Summix Limited is registered under Development of building projects (SIC 41100).
How old is Summix Limited?
Summix Limited was incorporated on 9 October 2006, 20 years ago.
What is the penalty if Summix Limited files its accounts late?
Companies House charges £150 if the accounts are up to 1 month late, £375 up to 3 months, £750 up to 6 months and £1,500 after that, doubled if the previous year's accounts were also late. HMRC charges £200 for a CT600 filed a day late and another £200 at 3 months.
Official records
View Summix Limited on Companies House for filed documents, officers and the full history.
Based on the Companies House register (snapshot 1 Oct 2026). Deadlines are worked out from the register and assume a standard accounting period; a change of year end or a short period moves them. This page is general information, not tax or accountancy advice.