| Comx Professional Services Limited | Chislehurst | 2012 |
| Comyn Limited | London | 2003 |
| Conacher Ltd | Dunning | 2020 |
| Conber DE Jong Ltd | London | 2023 |
| Concentric Engineering Limited | Redditch | 1956 |
| Concentric Tipton Limited | Redditch | 1997 |
| Concentric VFP Limited | Redditch | 2005 |
| Concentus Limited | Yarm | 2016 |
| Concept Air Conditioning Limited | Leigh | 2012 |
| Concept Architecture & Structural Design Ltd | Barnsley | 2017 |
| Concept Aviation Training Ltd | London | 2018 |
| Concept Building Solutions Limited | Preston | 2002 |
| Concept Chemicals Ltd | Manchester | 2017 |
| Concept Consulting Ltd | London | 2003 |
| Concept Data Limited | Ruddington | 1984 |
| Concept Design Limited | Southampton | 2006 |
| Concept Developments (Chilworth) Ltd | Weybridge | 2015 |
| Concept Films Limited | London | 2003 |
| Concept FM Services Limited | Chichester | 2021 |
| Concept Funerals Limited | Manchester | 2011 |
| Concept Homes (Walton) Ltd | Weybridge | 2014 |
| Concept Homes Limited | Thatcham | 2000 |
| Concept Independent Solutions Ltd | Eastwood | 2014 |
| Concept Ingredients Ltd | Swansea | 2017 |
| Concept Life Sciences (Discovery) Limited | Chapel-En-Le-Frith | 2014 |
| Concept Press Limited | Braintree | 2013 |
| Concept Property UK (NO2) Limited | Newton-Le-Willows | 2024 |
| Concept Recruitment Solutions Limited | Wakefield | 2010 |
| Concept Space Industrial Limited | Beckenham | 2017 |
| Concept Windows Limited | Romford | 2012 |
| CONCEPT2020 Ltd | London | 2025 |
| CONCEPT2MARKET Limited | Nottingham | 2006 |
| CONCEPT50-DETAILING Ltd | Casnewydd | 2025 |
| Concepti Limited | Swaffham | 2015 |
| Conceptual Audio Equipment Limited | Ashford | 2011 |
| Conceptual Media Ltd | London | 2005 |
| Concepture Ltd | Bristol | 2002 |
| Concerts at Sea Limited | Swindon | 2012 |
| Concessions UK Limited | Kenilworth | 2007 |
| Concilio Capital Ltd | London | 2024 |
| Concor Limited | Manchester | 2006 |
| Concorde II Limited | Exeter | 2011 |
| Concorde III Limited | Exeter | 2011 |
| Concorde Industries Limited | Newport Pagnell | 1973 |
| Concorde Interiors (London) Limited | Doncaster | 2005 |
| Concorde Memorabilia Limited | Farnborough | 1993 |
| Concorde Professional Services Limited | Exeter | 2011 |
| Concordia Holdings Limited | London | 2025 |
| Concrete Art Ltd | Stirling | 2015 |
| Concrete Class Ltd | Kington | 2025 |
| Concrete Express Limited | Welwyn Garden City | 2011 |
| Concrete Harbor Limited | Borehamwood | 2003 |
| Concrete Homes Ltd | London | 2024 |
| Concrete Liverpool Limited | Liverpool | 2016 |
| Concrete Preparation Ltd. | Stirling | 2011 |
| Concrete Setting Ltd | Tividale | 2008 |
| Concrete Solutions Ltd | Welshpool | 2024 |
| Condell & Co. Holdings Limited | Wallasey | 2026 |
| Conder Limited | Doncaster | 1999 |
| Condics Procurement Ltd | London | 2008 |
| Conditioned Fitness Ltd | Orpington | 2025 |
| Condor Midco Limited | London | 2020 |
| Condor Structuring Ltd | Woodford Green | 2025 |
| Condor Trading Ltd | Salford | 2013 |
| Conducting Business Limited | Tunbridge Wells | 2002 |
| Conduiit Ltd | Newark | 2021 |
| Conduit Resourcing Limited | Towcester | 2012 |
| Condyle Limited | Northamptonshire | 1995 |
| Cone Limited | London | 2002 |
| Coneinn Marketing (UK) Limited | Coventry | 2016 |
| Coneston Limited | Glasgow | 1985 |
| CONEW1 Limited | London | 2017 |
| Coneygre Foundry Limited(The) | Leicester | 1925 |
| Conference Cambridge Limited | Cambridge | 2008 |
| Conference Ltd | London | 2002 |
| Conference Systems Limited | Royston | 2007 |
| Confide Limited | Nottingham | 1995 |
| Confidence Energy Central Asia Ltd | Colchester | 2008 |
| Confidence Fillers Limited | London | 2021 |
| Confidence Technical Co., Ltd. | London | 2017 |
| Confidence.Works Coaching Limited | London | 2021 |
| Confident Carers Ltd | Burgess Hill | 2012 |
| Confident English Ltd. | Bushey | 2012 |
| Confident Services Limited | London | 2004 |
| Confidential Consulting Services Limited | Hastings | 2000 |
| Confined Space Rescue Limited | Sheffield | 2018 |
| Conflict Analysis Network (CAN) Ltd | London | 2018 |
| Conflict Protection Limited | London | 2017 |
| Conform Limited | Ashford | 1998 |
| Conforti Centre Ltd. | Coatbridge | 2010 |
| Confreight (UK) Limited | Maldon | 2001 |
| Cong Chuang Industry Limited | London | 2021 |
| Congenital Heart UK Ltd | Bristol | 2019 |
| Congleton Constitutional Club Limited(The) | Cheshire | 1895 |
| Congo Connect Limited | Birmingham | 2019 |
| Congo Diamonds Public Limited Company | London | 2007 |
| Congrats Ltd | Manchester | 2023 |
| CONGREG8 Limited | Lincoln | 2020 |
| Congress Company Secretarial Services Ltd | Middlesex | 1998 |
| Congreve Property Developments Limited | Maldon | 2017 |