| Complete Claims Ltd | Cardiff | 2019 |
| Complete Communication Holdings Limited | Birmingham | 2015 |
| Complete Corporate Finance Limited | Cramlington | 2012 |
| Complete Cover Group Limited | Tarporley | 1998 |
| Complete Credit Consultancy Limited | Stratford-Upon-Avon | 2007 |
| Complete Developments Group Limited | Portsmouth | 2024 |
| Complete Electronics Holdings Ltd | Milton Keynes | 2026 |
| Complete Financial Fitness Ltd | Sutton | 2005 |
| Complete Financial Ltd | Belfast | 2023 |
| Complete Financial Services Limited | Olney | 2002 |
| Complete Financial Solutions Limited | Chelmsford | 2004 |
| Complete Financial Solutions NW Ltd | Hyde | 2016 |
| Complete Financial UK Trading Limited | Eastbourne | 2010 |
| Complete Financing Ltd | Glasgow | 2021 |
| Complete FS Limited | Southampton | 2012 |
| Complete Funding Solutions Limited | Widnes | 2017 |
| Complete Group Holdings Limited | Canterbury | 2015 |
| Complete Group Limited | Glasgow | 2009 |
| Complete Health and Protection Ltd | Coalville | 2019 |
| Complete Healthcare Solutions (Midlands) Limited | Bromsgrove | 2003 |
| Complete Highways Assets Limited | London | 2024 |
| Complete Holdings Group Limited | London | 2026 |
| Complete Investments Group Ltd | Warrington | 2022 |
| Complete Investments Ltd | London | 2026 |
| Complete Kitchens Holdings Ltd | Soham | 2024 |
| Complete Marine Freight Group Limited | Chichester | 2023 |
| Complete Mining Solutions (UK) Limited | London | 2024 |
| Complete Moling Services Holdings Limited | Rochester | 2020 |
| Complete Money Care Ltd | Nottingham | 2011 |
| Complete Mortgage Advice Centre Limited | Harrow | 2004 |
| Complete Mortgage Advice Ltd | Plymouth | 2021 |
| Complete Mortgage Solutions NI Ltd | Lisburn | 2007 |
| Complete Mortgage Solutions UK Limited | Birmingham | 2000 |
| Complete Mortgages (Harrogate) Ltd | Harrogate | 2020 |
| Complete Origin Ltd | Belfast | 2026 |
| Complete Property Finance Ltd. | Borehamwood | 2024 |
| Complete Protection South Ltd | Lee-On-The-Solent | 2016 |
| Complete Risk Management Solutions Ltd | Chelmsford | 2025 |
| Complete Security Limited | London | 1989 |
| Complete Solutions Holdings Ltd | Dudley | 2021 |
| Complete Ventures 1 Limited | Stoke-On-Trent | 2023 |
| Complete Ventures Acqco 1 Limited | Stoke-On-Trent | 2023 |
| Complete Wealth Management Ltd | London | 2003 |
| Complete Wealth Solutions Ltd | Cirencester | 2009 |
| Complete Worldwide Group Ltd | London | 2016 |
| Completely Financial Services Limited | Harrogate | 2004 |
| Completely Over the Top Limited | Guildford | 2017 |
| Completion Products Holdings Limited | Aberdeen | 2024 |
| Completus Group Ltd | Scarborough | 2025 |
| Complex Capital Limited | Cardiff | 2022 |
| Complex Claims International (Group) Ltd | Windsor | 2025 |
| Complex Holding Ltd | Kingsclere Newbury | 2019 |
| Complex Investment Ltd | Morden | 2018 |
| Complex Rehab Group Holdings Limited | Liskeard | 2024 |
| Complex to Clear Group Holdings 1 Limited | Stockport | 2023 |
| Complexas Holdings Ltd | Selby | 2025 |
| Complexas Investments Ltd | Selby | 2025 |
| Complexus Holdings Limited | Kettering | 2021 |
| COMPLI360 Limited | Wimbledon | 2018 |
| Compliance 100 Group Ltd | Stourbridge | 2024 |
| Compliance Advisory Services Ltd | Edinburgh | 2020 |
| Compliance and Training Solutions Limited | Colchester | 2005 |
| Compliance Consultants (Kent and Essex) Limited | Sunderland | 2007 |
| Compliance Consulting Holdings Limited | London | 2013 |
| Compliance PAL Limited | Cardiff | 2021 |
| Compliance Replay Ltd | Ottery St Mary | 2024 |
| Compliance Solutions Holdings Limited | Harrow | 2022 |
| Compliance Specialists Limited | Barnet | 2021 |
| Complianceone Group Limited | Stockport | 2022 |
| Complier Consultants Limited | Falkirk | 2026 |
| Complitech Ltd | York | 2025 |
| Complus Asset Management (UK) Limited | London | 2022 |
| Comply Logistics Limited | Leicester | 2013 |
| Comply Wise Ltd | London | 2020 |
| COMPLY365 Holdings (UK) Limited | Bradley Stoke | 2023 |
| Complycrypto Depository Limited | London | 2021 |
| Complyed Holdings Limited | Manchester | 2025 |
| Complymap Group Ltd | London | 2022 |
| Complymatic Limited | Ashford | 2015 |
| Complyport Limited | London | 2001 |
| Component Process and Repair Holdings Limited | Newton Abbot | 2017 |
| Component Solutions Holdings Limited | Thetford | 2021 |
| Composed Abodes Limited | Bury St. Edmunds | 2024 |
| Composite Design Studio Holdings Ltd | London | 2025 |
| Composite Prime Group Limited | Bingley | 2018 |
| Composites Bidco Limited | Leamington Spa | 2021 |
| Composites Innovation Group Ltd | Coalville | 2014 |
| Composites Manufacturing Holdings Limited | Portsmouth | 2026 |
| Composites Topco Limited | Leamington Spa | 2021 |
| Compound Best Ltd | Liverpool | 2024 |
| Compound Empire Holdings Ltd | London | 2026 |
| Compound Good Ltd | South Croydon | 2014 |
| Compound Group Limited | London | 2026 |
| Compound Management (UK) Limited | London | 2011 |
| Compound Mind Ltd | Poole | 2021 |
| Compound Solutions (Holdings) Limited | Hadfield | 2025 |
| Compounding Equity Investment UK Ltd | Chelmsford | 2022 |
| Compounding Holdings Ltd | Leyland | 2026 |
| Compre Corporate Member 1 Limited | London | 2017 |
| Compre Corporate Member 2 Limited | London | 2019 |