| Com&Cam Security Services Ltd | Administrative & support | 2020 |
| Combined Motor Services Ltd | Wholesale & retail | 2022 |
| Combline Limited | Administrative & support | 2022 |
| Comfier Sleep LLP | | 2016 |
| Comfig Networks Limited | Professional & scientific | 2001 |
| Comfort Dwelling Ltd | Real estate | 2024 |
| Comfort Technology Limited | Wholesale & retail | 2019 |
| Comfy Care Living Limited | Health & social care | 2024 |
| Comfy Sports Ltd | Wholesale & retail | 2026 |
| Comfy Travel Ltd | Transport & logistics | 2024 |
| Comm Investments Limited | Wholesale & retail | 2003 |
| Command Communication Ltd | Information & communication | 2018 |
| Commander Logistics Limited | Transport & logistics | 2011 |
| Commercial - I Ltd | Real estate | 2015 |
| Commercial GAS & Electricity Limited | Other services | 2013 |
| Commercial Kitchen Extractor Repair Ltd | Administrative & support | 2025 |
| Commercial Solutions (MC) Ltd | Extraterritorial | 2005 |
| Commercialenergyrenewal Ltd | Information & communication | 2025 |
| Commodit Ltd | Information & communication | 2025 |
| Commodity BIZ (UK) Ltd | Wholesale & retail | 2012 |
| Common Time Ltd | Wholesale & retail | 2025 |
| Commonwealth Holdings Limited | Financial services | 2025 |
| Commonwealth Property Ltd | Real estate | 2003 |
| Communications Media Ltd | Professional & scientific | 2012 |
| Community Action Redbridge | Health & social care | 1990 |
| Community Care East CIC | Hospitality | 2024 |
| Community Care Transportation Ltd | Transport & logistics | 2026 |
| Community Empowerment & Youth Pathways CIC | Education | 2026 |
| Community Strength Security Services Ltd | Administrative & support | 2026 |
| Comno Ltd | Health & social care | 2018 |
| Comp Solutions Ltd | Information & communication | 2022 |
| Comp-Benation Ltd | Real estate | 2021 |
| Compact DOM & COM Repairs Ltd | Other services | 2024 |
| Companies Blue Limited | Construction | 2011 |
| Companies Plus Services Limited | Professional & scientific | 2016 |
| Company Restorations Limited | Professional & scientific | 2023 |
| Compare Insurex Ltd | Professional & scientific | 2023 |
| Compassion Healthcare Training Centre Ltd | Wholesale & retail | 2024 |
| Compassionate Care Support Ltd | Health & social care | 2021 |
| Competitive HGV Transport Ltd | Transport & logistics | 2023 |
| Compile Consultancy Limited | Information & communication | 2016 |
| Complete Engineering and Construction Limited | Professional & scientific | 2022 |
| Complete FIX Ltd | Other services | 2019 |
| Compliance Energy Ltd | Construction | 2014 |
| Compliance Recruitment Ltd | Administrative & support | 2020 |
| Compliance Trading Ltd | Other services | 2018 |
| Complydefend Technologies Ltd | Information & communication | 2025 |
| Complywise Digital Limited | Information & communication | 2025 |
| Composite Care Ltd | Manufacturing | 2025 |
| Composite Trade UK Ltd | Manufacturing | 2011 |
| Comprobase Ltd | Information & communication | 2023 |
| Compushop Limited | Other services | 2013 |
| Computech+ Ltd | Information & communication | 2016 |
| Computer & Smartphone Clinic Ltd | Other services | 2017 |
| Computer Clinic Limited | Wholesale & retail | 2022 |
| Computer Concern Limited | Information & communication | 2021 |
| Computer Techno Solutions Ltd | Information & communication | 2012 |
| Computer Troubleshooters Redbridge Limited | Information & communication | 2014 |
| Computershooter Limited | Other services | 2007 |
| Comtel Ltd | Information & communication | 2023 |
| Concept Assets Limited | Real estate | 2020 |
| Concept Central Limited | Wholesale & retail | 2003 |
| Concept Construction Consultancy Ltd | Professional & scientific | 2018 |
| Concious Actionz Ltd | Wholesale & retail | 2024 |
| Concord Pharma Services (UK) Ltd | Professional & scientific | 2016 |
| Condor Facilities Services Ltd | Administrative & support | 2025 |
| Confido Proprietas Group Limited | Real estate | 2021 |
| Coningsby Javs Limited | Health & social care | 2019 |
| Coniston Derwent Limited | Information & communication | 2023 |
| Conix Star Ltd | Construction | 2026 |
| Connaught Avenue Essex Limited | Construction | 2013 |
| Connaught House Ltd | Real estate | 2018 |
| Connaught Mews Residents Limited | Households | 2004 |
| Connect Building Supplies Ltd | Wholesale & retail | 2015 |
| Connect Growth Ltd | Professional & scientific | 2022 |
| Connect Hub Ltd | Wholesale & retail | 2022 |
| Connect Parcel Services Ltd | Transport & logistics | 2025 |
| Connecting Families & Communities Ltd | Health & social care | 2025 |
| Connecting Wholesale Trade Limited | Wholesale & retail | 2023 |
| CONNECTIONS4UK Ltd | Education | 2024 |
| Connexa Limited | Other services | 2017 |
| Connica Investments Limited | Administrative & support | 2005 |
| Connoisseurcollective Limited | Arts & recreation | 2019 |
| Conoria Solutions Ltd | Construction | 2025 |
| Conqr Media Ltd | Information & communication | 2024 |
| CONS12 Limited | Construction | 2025 |
| CONS2 Limited | Construction | 2025 |
| Conservative Friends of Nigeria | Other services | 2021 |
| Conservative Friends of South Asia Ltd | Other services | 2024 |
| Constack Limited | Professional & scientific | 2018 |
| Constantine Way Stores Ltd | Wholesale & retail | 2019 |
| Construct HQ Limited | Construction | 2023 |
| Constructfutures Limited | Real estate | 2017 |
| Construction Boost Ltd | Administrative & support | 2017 |
| Construction City Limited | Construction | 2021 |
| Construction Compliance Group Ltd | Construction | 2026 |
| Construction Invest Decisions LLP | | 2017 |
| Construction Logistics Services Limited | Construction | 2017 |
| Construction Plant Competence Training Ltd | Administrative & support | 2022 |
| Construction Unlimited Time Limited | Construction | 2026 |