| Conceptus UK Limited | Hull | 2000 |
| Concert Audio Communications Limited | Burton-On-Trent | 1997 |
| Concert Pitch Music Ltd | Ashford | 2018 |
| Concession Sports Ltd | Gerrads Cross | 2009 |
| Conch Clothing Limited | Brighton | 2015 |
| Conch Development Limited | Middlesbrough | 2019 |
| Concierge-Europe.Com Ltd | Cheltenham | 2007 |
| Concility Limited | Leicester | 2016 |
| Concise Fabrications Limited | Ringwood | 2016 |
| Conco SV Ltd | Sheffield | 2021 |
| Concor Trading Limited | Dundee | 2026 |
| Concorba Limited | Salisbury | 2007 |
| Concord Copying (1995) Limited | Glasgow | 1995 |
| Concord Fabrics (UK) Limited | Maidenhead | 1999 |
| Concord Products Ltd | Bridgnorth | 2019 |
| Concord Security (Alarm) Systems Limited | Middlesex | 1986 |
| Concorde Commercial Maintenance Limited | Aldridge | 1998 |
| Concorde Glass Limited | Mablethorpe | 1987 |
| Concorde I Limited | Exeter | 1989 |
| Concorde Tool & Gauge Ltd | Coventry | 2008 |
| Concorde Yachting Ltd | Castleford | 2025 |
| Concordia Electrical Services Ltd | Warrington | 2022 |
| Concours Carpets Limited | Witney | 2021 |
| Concours Lifts Ltd | Doncaster | 2016 |
| Concours Plating Ltd | Birmingham | 2018 |
| Concours Tyre and Rubber Products International Limited | Uttoxeter | 1999 |
| Concourse (UK) Ltd | Dunfermline | 2014 |
| Concreations Limited | Chelmsford | 2006 |
| Concrete & Screed MIX Ltd | Gravesend | 2025 |
| Concrete 7 Days Ltd | Motherwell | 2026 |
| Concrete and Quarry Services Ltd | Maghera | 2025 |
| Concrete Batching Systems Limited | | 2009 |
| Concrete Boost Limited | Hounslow | 2019 |
| Concrete Building Solutions Limited | Stockport | 2023 |
| Concrete Business Ltd. | Bridgend | 2006 |
| Concrete Butterflies Media Ltd | Inverness | 2017 |
| Concrete Canvas Group Limited | Pontyclun | 2011 |
| Concrete Canvas Kyrgyzstan Limited | Pontyclun | 2025 |
| Concrete Canvas Limited | Pontyclun | 2005 |
| Concrete Canvas Properties Limited | Pontyclun | 2013 |
| Concrete Canvas Technology Ltd. | Pontyclun | 2011 |
| Concrete Carrot Ltd | Penarth | 2013 |
| Concrete Corrosion Tech Ltd | Birmingham | 2021 |
| Concrete Creations (UK) Limited | Newbury | 2014 |
| Concrete ETC Ltd | London | 2019 |
| Concrete Fabrications Limited | Bristol | 1999 |
| Concrete Floor Products Limited | Redditch | 2018 |
| Concrete in Motion Ltd | London | 2025 |
| Concrete Innovations Ltd | Newark | 2018 |
| Concrete Island Brewery Limited | London | 2016 |
| Concrete Made Easy Limited | Thornton-Cleveleys | 2020 |
| Concrete MAN Ltd | Faringdon | 2019 |
| Concrete MIX Master Limited | Slough | 2022 |
| Concrete MIX Services Ltd | Hounslow | 2021 |
| Concrete Panel Limited | Nottingham | 2012 |
| Concrete Panel Systems Limited | Wrenbury | 2009 |
| Concrete Preservation Technologies Ltd | Long Eaton | 2005 |
| Concrete Pumping London Limited | London | 2022 |
| Concrete Sales Ltd | Epsom | 2016 |
| Concrete Solutions Yorkshire Limited | Doncaster | 2024 |
| Concrete Southern Ltd | London | 2022 |
| Concrete Taxi Limited | Dewsbury | 2013 |
| Concrete Taxi Readymix Ltd | Dewsbury | 2023 |
| Concrete Wall Panels Limited | Carlisle | 2015 |
| Concrete Wetcast Machinery Ltd | Armagh | 2023 |
| CONCRETE4CHANGE Ltd | Nottingham | 2021 |
| CONCRETE4U1 Limited | Wolverhampton | 2023 |
| Concretemade Ltd | Ilkeston | 2020 |
| Concreum & Co. Ltd | London | 2026 |
| Concrush Plant Ltd | Castlederg | 2022 |
| Concurrent Solutions Limited | Worcester | 1984 |
| Concurrent Technologies PLC | Colchester | 1985 |
| Condale Plastics Limited | East Grinstead | 1970 |
| Condecor Ltd | Mosley | 2018 |
| Condensate Systems Limited | Cannock | 2016 |
| Condensation Mould Solutions Ltd | Northwich | 2022 |
| Condessa Limited | Holyhead | 2019 |
| Condex (UK) Limited | Lancaster | 1997 |
| Condimaniac Limited | Chatham | 2019 |
| Condiment Cupboard Ltd | Birkenhead | 2025 |
| Condimental Ltd | Truro | 2016 |
| Condimentum Limited | Norwich | 2017 |
| Condition Monitoring Technology Group Holdings Limited | Torrington | 2021 |
| Condition Monitoring Technology Group Limited | Torrington | 2006 |
| Conditionaire International Limited | Sevenoaks | 2009 |
| Condor Aviation Skybikes Limited | Selby | 2022 |
| Condor Engineering Group Limited | Selby | 2001 |
| Condor Systems Ltd | Guildford | 2025 |
| Condor Technologies Limited | Weybridge | 2005 |
| Condor Verde (UK) Trading Ltd | York | 2025 |
| Conductix-Wampfler Ltd | Salford | 1978 |
| Conduit Construction Network Limited | Durham | 2005 |
| Cone 10 Ltd | Edinburgh | 2025 |
| Cone 6 Ceramics Ltd | London | 2023 |
| Cone Heid Ltd | Edinburgh | 2026 |
| Cone Seafoods Limited | Grimsby | 2024 |
| Conectapipe Limited | Wirral | 2014 |
| Conectid Limited | Reading | 2017 |
| Conex Tooling Solutions Ltd | Billingham | 2023 |
| Coney Bakery Limited | Kettering | 2018 |