| Colwells Enterprises Limited | Hitchin | 1989 |
| Colwells Services Ltd | Banbury | 2020 |
| Colwith Farm Distillery Limited | Par | 2015 |
| Colwith Farm Potatoes Limited | Truro | 2019 |
| Colyer Thorpe Limited | Manchester | 1975 |
| Colzam UK Ltd | London | 2026 |
| COM - PAK Design Limited | Ilkeston | 1987 |
| COM Services (West Midlands) Limited | Lythan St Annes | 2013 |
| Com.Net (Cabling) Limited | Dudley | 2000 |
| Comac Ltd | Belfast | 2019 |
| Comac Machinery Ltd | Dovercourt Harwich | 1996 |
| Comac Precision Engineering Ltd. | Motherwell | 2006 |
| Comac Robotics UK Ltd | Enfield | 2026 |
| Coman-Ri Ltd | Cambridge | 2024 |
| Comanche Biopharma (UK) Limited | Altrincham | 2022 |
| Comantec Limited | London | 1987 |
| Comar Engineering Services Limited | Coventry | 1978 |
| Comar Optics Limited | Haverhill | 2013 |
| Comar Systems Ltd | Newport | 2015 |
| Comari Ltd | London | 2026 |
| Comart Healthcare Limited | Rotherham | 2023 |
| Comax Systems UK Limited | Rotherham | 2025 |
| Combass Limited | Killamarsh | 1978 |
| Combat Commissioning Services Limited | Sutton Coldfield | 2011 |
| Combat Doors Limited | Manchester | 2001 |
| Combat Fuel Supplements Limited | Andover | 2021 |
| Combat Heating Solutions Limited | Wednesbury | 2017 |
| Combat Medical Ltd | St Albans | 2012 |
| COMBAT2 Limited | Ipswich | 2026 |
| COMBAT2COFFEE C.I.C. | Ipswich | 2018 |
| Combathippy Ltd | Sherborne | 2025 |
| Combayti France Ltd | Birmingham | 2025 |
| Combe 90 Engineering Ltd | Eastbourne | 2024 |
| Combe Brewing Company Ltd | Ilfracombe | 2012 |
| Combe International Limited | Leatherhead | 1974 |
| Combe Martin Meats Limited | Barnstaple | 2017 |
| Combi (North East) Limited | Middlesbrough | 2002 |
| Combi Heat Services Limited | Downend | 2016 |
| Combi Pro UK Ltd | Kidderminster | 2023 |
| Combi World Limited | Tunbridge Wells | 2015 |
| Combi-Fix Solutions Limited | Bourne | 2013 |
| Combi-Tech Ltd. | Basildon | 2013 |
| Combi-Vent Engineering Limited | Manchester | 1994 |
| Combicat Ltd | Milton Keynes | 2013 |
| Combicut Limited | Reading | 1980 |
| Combilift N.I. Limited | Armagh | 2025 |
| Combinatorial Chemistry Solutions Limited | Cambridge | 1998 |
| Combind Industries Ltd | Startford Upon Avon | 2019 |
| Combine Chemicals Limited | Burlescombe | 2024 |
| Combine Fabs Ltd | Nottingham | 2011 |
| Combine Pallet Co. Limited | Norfolk | 1969 |
| Combine Rescue Ltd | Daventry | 2022 |
| Combined Air Limited | Wellingborough | 2016 |
| Combined Brewery Services Limited | Halifax | 1992 |
| Combined Catering Services Ltd | Bootle | 1990 |
| Combined Elements Ltd | Walsall | 2025 |
| Combined Framemakers Limited | Herne Bay | 1996 |
| Combined Heat and Power Investments Limited | London | 2015 |
| Combined Insulations and Plastics Limited | Bedford | 1990 |
| Combined Logical Solutions Ltd. | Carterton | 2001 |
| Combined Marine Services Ltd | Ivybridge | 2019 |
| Combined Photographic & Electronic Services (Europe) Limited | Stoke On Trent | 2003 |
| Combined Pumps Corp Ltd | Aberdeen | 1998 |
| Combined Pumps Corporation International Limited | Aberdeen | 2026 |
| Combined Services (GB) Limited | Princes Risborough | 1992 |
| Combined Test Solutions Ltd | Leighton Buzzard | 2014 |
| Combiwave Ltd | Walsall | 2024 |
| Combogreen (UK) Limited | Edinburgh | 2022 |
| Combro Limited | Seaford | 2006 |
| Combust Boiler Services Ltd | Porth | 2019 |
| Combustion Engineering Ltd | Derbyshire | 1948 |
| Combustion Specialist Services Ltd | Stockport | 2026 |
| Combustion Technology International Limited | Stamford | 2017 |
| Combuy Limited | Hengoed | 1999 |
| Combwell Wood Products Limited | Maidstone | 2024 |
| Comcat Electrical Limited | Nottingham | 2019 |
| Comcat Engineering SW Ltd | Newton Abbot | 2019 |
| Comcoplast UK Limited | London | 2020 |
| Comcorde IQ Limited | London | 2022 |
| Comcount Limited | Kidderminster | 1985 |
| Comdev Creative Limited | Leicester | 2018 |
| Comdronic Limited | Cheltenham | 2014 |
| Come 4 Sleep Limited | Dewsbury | 2015 |
| Come AS YOU ARE Enterprise Ltd | Cardiff | 2019 |
| Comeca UK Limited | Stoke-On-Trent | 2014 |
| Comech Engineering Ltd | Omagh | 2016 |
| Comed Ltd | Manchester | 2021 |
| Comedo Limited | Manchester | 2021 |
| Comelit Group UK Limited | Ormskirk | 2021 |
| Comelit-Gdxpac Limited | Ormskirk | 2021 |
| Comelit-Pac Limited | Luton | 2001 |
| Comelit-Pacgdx Limited | Ormskirk | 2021 |
| Comeout Ltd | London | 2026 |
| Comer (UK) Ltd | Leeds | 1995 |
| Comer Plating Limited | Coventry | 2000 |
| Comercial Investment of UK Limited | London | 2024 |
| Comergy Limited | Hampshire | 1997 |
| Comet Catering Equipment Co. Limited | Enfield | 1979 |
| Comet Coffee Ltd | Wadhurst | 2025 |
| Comet Customs Ltd | Fleet | 2023 |