| Comma Housing Ltd | Health & social care | 2023 |
| Commercial and Residential Screeders Limited | Construction | 2008 |
| Commercial Audit Services Ltd | Real estate | 2013 |
| Commercial Collection Services Limited | Administrative & support | 1988 |
| Commercial Intermediary Business Ltd | Wholesale & retail | 2026 |
| Commercial Prop.Info Limited | Real estate | 2010 |
| Commit Developments Ltd | Real estate | 2021 |
| Commodity Hub Ltd | Information & communication | 2011 |
| Commodore Real Estate Limited | Real estate | 2023 |
| Common Cafe Ltd | Real estate | 2025 |
| Common Collective Group Limited | Information & communication | 2025 |
| Common View Management Company Limited | Households | 2002 |
| Communal Response Group Limited | Administrative & support | 2023 |
| Community Benefit Action C.I.C. | Professional & scientific | 2009 |
| Community Care Management Limited | Health & social care | 2025 |
| Community Clean Ltd | Administrative & support | 2020 |
| Community Coaching Hall CIC | Education | 2023 |
| Community Elderly Support CIC | Health & social care | 2023 |
| Community Frontline Impact Service Limited | Education | 2021 |
| Community Leaders CIC | Administrative & support | 2023 |
| Community Liberation C.I.C. | Education | 2025 |
| Community Pharmacies (UK) Limited | Professional & scientific | 2009 |
| Como Bay Ltd | Real estate | 2026 |
| Compact Care Solutions Ltd | Administrative & support | 2018 |
| Compact Investments Ltd | Financial services | 2023 |
| Companion Traders Ltd | Wholesale & retail | 2023 |
| Company Formations Maria Evans Private Limited | Administrative & support | 2015 |
| Company Named Limited | Information & communication | 2021 |
| Company of Builders Ltd | Construction | 2020 |
| Compare Travel Group Limited | Administrative & support | 2016 |
| Compass Court (Bath) Limited | Households | 1999 |
| Compassion Outreach Network Ministries | Other services | 2014 |
| Competent (Reps) Limited | Professional & scientific | 2015 |
| Compitech Technology Services Limited | Information & communication | 2022 |
| Complete Marine Marketing Ltd | Professional & scientific | 2024 |
| Compliant Business Services Limited | Professional & scientific | 2008 |
| Comport Green Construction Ltd | Construction | 2015 |
| Comprehensive Service Facilities Limited | Administrative & support | 2007 |
| Comproin Limited | Real estate | 2014 |
| Compton Way Residents Association Limited | Households | 2005 |
| Compukonnect Limited | Education | 2022 |
| Compuserve Services Partners LLP | | 2015 |
| Computer Assisted Developments Limited | Wholesale & retail | 2008 |
| Computing Excellence Ltd | Information & communication | 2001 |
| Comrespro Assets Limited | Real estate | 2021 |
| Comtrac Ltd | Information & communication | 2011 |
| Comun Ltd | Wholesale & retail | 2025 |
| Conal Court RTM Company Limited | Households | 2009 |
| Conattru Limited | Professional & scientific | 2015 |
| Concept-Morph Ltd | Real estate | 2018 |
| Concerto Corporate Catering Ltd | Hospitality | 2023 |
| Conchitas Limited | Hospitality | 2000 |
| Concorde Travel Solutions Limited | Administrative & support | 2018 |
| Concordia Properties (UK) Limited | Real estate | 2024 |
| Conder Radiology Services Limited | Health & social care | 2016 |
| Conditions Limited | Education | 2018 |
| Conditions Online Limited | Education | 2024 |
| Conductor Technology International Services Ltd | Transport & logistics | 2026 |
| Conduit Art Limited | Wholesale & retail | 2025 |
| Confederation of Passenger Transport UK | Other services | 1974 |
| Conference Dynamics Limited | Information & communication | 1993 |
| Confidence Foods Ltd | Wholesale & retail | 2017 |
| Confirmed Anomalies CIC | Other services | 2022 |
| CONGRATS25 Ltd | Construction | 2025 |
| Coniston House Management Limited | Households | 2000 |
| Conix International (U.K.) Co. Limited | Wholesale & retail | 1997 |
| Connaught Road (Folkestone) Ltd | Households | 2017 |
| Connect Community C.I.C. | Other services | 2019 |
| Connect Services DJC Ltd | Manufacturing | 2021 |
| CONNECT2PHARMA Ltd | Professional & scientific | 2015 |
| Connected Builders Ltd | Construction | 2023 |
| Connectinglogic Limited | Information & communication | 2025 |
| Connection Home Setup Ltd | Wholesale & retail | 2025 |
| Connects Services Ltd | Energy | 2021 |
| Connexus Consultants & Co Ltd | Professional & scientific | 2015 |
| Conputant Limited | Information & communication | 2013 |
| Conqueren Global Trading Ltd | Wholesale & retail | 2026 |
| Conquest Trading Limited | Arts & recreation | 2016 |
| Conscious Muslim Ltd | Health & social care | 2021 |
| Consensory Networks Limited | Professional & scientific | 2013 |
| Conseq Group Ltd | Administrative & support | 2017 |
| Conservatory Collections Ltd | Construction | 2007 |
| Consider 64 Ltd | Other services | 2020 |
| CONSIDER64 Holdings Limited | Financial services | 2025 |
| CONSIDER64 Lettings Limited | Real estate | 2025 |
| Consilience Group Ltd | Information & communication | 2017 |
| Consistance Ltd | Wholesale & retail | 2025 |
| Consortiq Limited | Education | 2015 |
| Constable Mews Management Limited | Households | 2017 |
| Constantine & Co Jewellers Ltd | Wholesale & retail | 2023 |
| Constellations London Ltd | Construction | 2015 |
| Construction & Engineering Design Ltd | Construction | 2014 |
| Construction Duty Ltd | Administrative & support | 2020 |
| Construction EYE Ltd | Professional & scientific | 2025 |
| Construction New Life Ltd | Construction | 2023 |
| Construction Planners Limited | Construction | 2024 |
| Construction Revolution Ltd | Public administration | 2026 |
| Construction S&I Limited | Construction | 2018 |
| Construction Site Labour General Ltd | Construction | 2025 |
| Constructionandengineeringopportunities (CEO) CIC | Education | 2022 |