| Clarkson Developments (Holdings) Ltd | Workington | 2023 |
| Clarkson Evans Group Limited | Gloucester | 2022 |
| Clarkson Group Holdings Ltd | Glasgow | 2024 |
| Clarkson Holdings Group Limited | Hull | 2026 |
| Clarkson Sales Consulting Ltd | Billericay | 2024 |
| Clarkson Shipping Investments Limited | London | 2002 |
| Clarkson's Holdings Ltd | Oxford | 2019 |
| Clarksons Structured Asset Finance Limited | London | 2000 |
| Clarkstoun Ltd | Glasgow | 2017 |
| Clarksville Limited | Belfast | 2014 |
| Clarky Limited | Billericay | 2025 |
| Clarlien Limited | London | 2024 |
| Clarmond Wealth Limited | Basildon | 2013 |
| Clarnor Estates Holdings Limited | Northampton | 2021 |
| Clarnor Holdings Limited | Coventry | 2019 |
| Claro Pall Mall Ltd. | Leigh-On-Sea | 2016 |
| Claro Risk Management Limited | Liverpool | 2025 |
| Claro Wealth Limited | London | 2019 |
| Claronex Limited | London | 2016 |
| Clarshire Holdings Ltd | Purley | 2026 |
| Clarus Technology Holdings Ltd | London | 2024 |
| Clarus Technology Ltd | London | 2025 |
| Clarus Wealth Limited | Woking | 2012 |
| Clas Consultancy Limited | Washington | 2021 |
| Clas Investment Holdco Limited | London | 2024 |
| Clas Investment Limited | London | 2024 |
| Clas Jaguar 2 Limited | London | 2025 |
| Clas Jaguar Holdco Limited | London | 2026 |
| Clas Jaguar Limited | London | 2025 |
| Clas Jaguar Nominee 1 Limited | London | 2025 |
| Clas Jaguar Nominee 2 Limited | London | 2025 |
| Clas Puma 2 Limited | London | 2025 |
| Clas Puma Limited | London | 2025 |
| Clas Puma Nominee 1 Limited | London | 2025 |
| Clas Puma Nominee 2 Limited | London | 2025 |
| Clas World Limited | Ilford | 2023 |
| Clasc Holdings Ltd | Bicester | 2025 |
| Clasco Property Limited | Warlingham | 2024 |
| Clasen+Co. Limited | London | 2010 |
| Clashea Holdings Ltd | London | 2022 |
| Clasp Holdings Ltd | Tunbridge Wells | 2018 |
| Class 1 Group Ltd | Winchester | 2025 |
| Class Carnet Ltd | London | 2012 |
| Class Management Holdings Limited | Chelmsford | 2020 |
| Classgrade Holdings Limited | London | 2023 |
| Classhouse Holdings Limited | South Shields | 2016 |
| Classic Acquisitions Limited | Fareham | 2024 |
| Classic Bloodstock & Equine Ltd | Maldon | 2025 |
| Classic Blue Ltd | London | 2016 |
| Classic Car Club Holdings Limited | Hornchurch | 2000 |
| Classic Fork Truck Holdings Limited | Nuneaton | 2026 |
| Classic Glazing Holdings Limited | Castleford | 2023 |
| Classic Golf International Holdings Ltd | Eastleigh | 2018 |
| Classic Grand Holding Ltd | Glasgow | 2025 |
| Classic Line Insurance Services Limited | Leicester | 1992 |
| Classic Marble (Showers) Holding Ltd | Dungannon | 2022 |
| Classic Mortgages Partnership Ltd | Handforth | 2007 |
| Classic Motor Auctions Limited | Barnsley | 2024 |
| Classic Network Solutions Ltd | Peterborough | 2003 |
| Classic Rowan Ltd | Leeds | 2022 |
| Classic Sourcing Solutions Limited | Towcester | 2023 |
| Classic Vehicle Valuation Services Ltd | Southampton | 2025 |
| Classicus Ltd | Woking | 2015 |
| Classifieds Group Limited | London | 2021 |
| Classroom Staff Sickness Ltd | Bradford | 2018 |
| Classworx Holdings Limited | Macclesfield | 2026 |
| Classy Property Investment Limited | Thornton Heath | 2022 |
| Classypaws Limited | Dereham | 2008 |
| Clatfielding Limited | London | 2013 |
| Clatterford Holdings Limited | Tunbridge Wells | 2019 |
| Clatts Investments Ltd | Brentwood | 2025 |
| Claude Bosi Investments Ltd | Milton Keynes | 2023 |
| Claude Goldsmith Group Holdings Limited | Leigh On Sea | 2007 |
| Claude Hooper Holdings Limited | Tunbridge Wells | 2020 |
| Claudius Investments Limited | London | 2019 |
| Claven Group Limited | Lamport | 2017 |
| Claverdale Limited | London | 2005 |
| Clavering Holdings Limited | Northumberland | 2022 |
| Claverton Group Limited | Hayes | 2020 |
| Claves Mercurii Holding Limited | London | 2023 |
| Clavestra Digital Holdings Ltd | Mildenhall | 2023 |
| Clavis Partners Limited | London | 2012 |
| Clavitron (Nominees) Limited | Wigan | 2000 |
| Clavius Capital Ltd | London | 2023 |
| Claw Kingdom Ltd | Leicester | 2025 |
| Claxton Associates Limited | Watford | 2001 |
| Claxton PMF Limited | Great Yarmouth | 2025 |
| Claxum Group Ltd | Chippenham | 2026 |
| Clay Capital Ltd | Bude | 2025 |
| Clay Corporation Limited | Portsmouth | 2025 |
| Clay Cross Asset Management Ltd | Oxford | 2014 |
| Clay GBP Holdings Ltd | Bromsgrove | 2023 |
| Clay Group Investments Limited | Bromsgrove | 2019 |
| Clay Holdings Ltd | Sheffield | 2026 |
| Clay PIT Street Whitchurch Ltd | Shrewsbury | 2019 |
| Clay Ventures Limited | London | 2022 |
| Clay Wealth Management Limited | Leamington Spa | 2013 |
| Claybell Limited | Milton Keynes | 2012 |
| Clayborn Holdings Limited | Ossett | 2024 |
| Claybridge Financial Planning Ltd | Ilford | 2009 |