| Clunie Care Limited | Health & social care | 2022 |
| Clusaz Limited | Administrative & support | 2005 |
| Cluvo Limited | Wholesale & retail | 2025 |
| Clwr International Realty Limited | Real estate | 2025 |
| CLX Sofas Limited | Wholesale & retail | 2013 |
| Clyde Mechanical Services Limited | Construction | 2006 |
| CM Carpentry Contractors Limited | Manufacturing | 2023 |
| CM Frost Autoparts Limited | Wholesale & retail | 2003 |
| CM Growfresh Limited | Agriculture & fishing | 2011 |
| CM Management Consultants Ltd | Professional & scientific | 2017 |
| CM Racing Ltd | Arts & recreation | 2025 |
| Cm&Aa Limited | Wholesale & retail | 2025 |
| Cm-I Tracewithouttrack Limited | Information & communication | 2025 |
| CM4 Intelligence Ltd | Information & communication | 2025 |
| CMA Sports Horses Ltd | Agriculture & fishing | 2025 |
| CMA Tyres Ltd | Wholesale & retail | 2025 |
| Cmart Stores Ltd | Wholesale & retail | 2022 |
| CMC Cevenini UK Ltd | Wholesale & retail | 2019 |
| CMC Installations Limited | Construction | 2014 |
| CMC Media Ltd | Professional & scientific | 2013 |
| CMC Performance Cars Ltd | Wholesale & retail | 2021 |
| CMC Trading Ltd | Wholesale & retail | 2017 |
| Cmcsmoketech Ltd | Other services | 2025 |
| CMD Property Developments Limited | Real estate | 2015 |
| CMD Top Logistic Ltd | Transport & logistics | 2021 |
| CMI Drylining Ltd | Construction | 2019 |
| CMJ Consulting Limited | Professional & scientific | 2019 |
| CML Industrial Services Limited | Professional & scientific | 2017 |
| CML Solutions Ltd | Financial services | 2025 |
| CMP Trans Ltd | Transport & logistics | 2019 |
| Cmrj Distribution Ltd | Wholesale & retail | 2026 |
| CMS Connect Ltd | Professional & scientific | 2017 |
| CMT Property Group Limited | Real estate | 2025 |
| CMT Road Transport Ltd | Transport & logistics | 2022 |
| CN Holdings (Wellingborough) Limited | Financial services | 2026 |
| CN Northampton Limited | Education | 2023 |
| CN Sales Recruitment Limited | Administrative & support | 2010 |
| CNC Creations Ltd | Extraterritorial | 2024 |
| CNC Innovations Ltd. | Professional & scientific | 2012 |
| CNC IT NOW Limited | Manufacturing | 2013 |
| CND Advisors Ltd | Professional & scientific | 2022 |
| CNG Productions Ltd | Wholesale & retail | 2017 |
| CNH Print Ltd | Manufacturing | 2018 |
| CNN Industrial Roofing Ltd | Construction | 2024 |
| CNN Roofing Ltd | Construction | 2021 |
| CNS Heating, Plumbing and Air Conditioning Ltd | Construction | 2026 |
| CNS Partners Ltd | Administrative & support | 2018 |
| Co-Mech Ltd | Construction | 2020 |
| CO2 GAS & Heating Ltd | Construction | 2026 |
| Coach Canham Limited | Health & social care | 2024 |
| Coach Kwanz Ltd | Education | 2025 |
| Coalville Holdings Ltd | Financial services | 2018 |
| Coalville Van Centre Ltd | Wholesale & retail | 2016 |
| Coandaly Ltd | Manufacturing | 2023 |
| Coanzido Ltd | Transport & logistics | 2020 |
| Coates and Morgan Limited | Wholesale & retail | 2002 |
| Coba Education Ltd | Other services | 2012 |
| Coba Resourcing Ltd | Information & communication | 1997 |
| Cobalt Blue Design Limited | Administrative & support | 2023 |
| Cobblers' & Co. Limited | Households | 2023 |
| Cobbles Estate Agency Limited | Real estate | 2025 |
| Cobdes Ltd | Extraterritorial | 2021 |
| Cobley Desborough Limited | Professional & scientific | 2012 |
| Cobley Equipment Hire Limited | Administrative & support | 2008 |
| Cobra Couriers MK Limited | Transport & logistics | 2011 |
| Cobra Healthcare Ltd | Administrative & support | 2020 |
| Cochin Brews Ltd | Wholesale & retail | 2024 |
| Cochran, Harris & Clarke Limited | Professional & scientific | 2013 |
| Cock and Pullet Egglistics Limited | Agriculture & fishing | 2009 |
| Coco Cafe Ltd | Hospitality | 2025 |
| Coco Glazing Limited | Construction | 2015 |
| Cocoa Digital Media Ltd | Professional & scientific | 2015 |
| Coconut Beach Ltd | Hospitality | 2019 |
| Coconut County Limited | Information & communication | 2025 |
| Coconut Paradise Ltd | Hospitality | 2024 |
| Cod's Plaice Limited | Hospitality | 2011 |
| Coddington 10 Renewables Ltd | Professional & scientific | 2023 |
| Coddiwomple Property Investment Ltd | Real estate | 2023 |
| Code Global Limited | Information & communication | 2000 |
| Code Red Fire and Flood Ltd | Construction | 2018 |
| Codedgeek Limited | Information & communication | 2020 |
| Codenova Tech Ltd | Information & communication | 2025 |
| Coder and Pauper Ltd | Information & communication | 2020 |
| Codified Strategy Limited | Professional & scientific | 2025 |
| Codner Creative Limited | Information & communication | 2020 |
| Codrean Services Limited | Construction | 2019 |
| Codru Ltd | Construction | 2024 |
| Cogenhoe United Football Club Limited | Arts & recreation | 2020 |
| Cogenhoe United Youth Football Club Ltd | Arts & recreation | 2024 |
| Cogent Works Limited | Information & communication | 2011 |
| Coggeshall Residents Management Company Limited | Real estate | 2023 |
| Coggins Motors Limited | Wholesale & retail | 2009 |
| Coglock Ltd | Manufacturing | 2023 |
| Cogmusk Holdings Limited | Financial services | 2026 |
| Cogmusk Limited | Financial services | 2001 |
| Cognerys Ltd | Information & communication | 2025 |
| COH Engineering Ltd | Professional & scientific | 2023 |
| Cohaus Ltd | Real estate | 2017 |
| Cohesive Society CIC | Administrative & support | 2017 |
| Cohnab Limited | Manufacturing | 1998 |