| Commercial Space Solutions Limited | Real estate | 2024 |
| Commercial Ventilation Services Ltd | Manufacturing | 2010 |
| Community Care York Ltd. | Health & social care | 2015 |
| Community Integration & Recovery Centre (Circ) C.I.C. | Administrative & support | 2026 |
| COMP4 Limited | Information & communication | 2016 |
| Companies Formation, Hosting & Operation Ltd | Administrative & support | 2021 |
| Compass Enterprises Limited | Administrative & support | 2008 |
| Compassionate Health Limited | Health & social care | 2019 |
| Competitive Edge Marketing Limited | Professional & scientific | 2003 |
| Complete Biomass Solutions Ltd | Energy | 2021 |
| Complete Commercial Property Ltd | Real estate | 2021 |
| Complete Homes and Property Ltd | Real estate | 2021 |
| Complete Interior Solutions Ltd | Construction | 2010 |
| Complete Safety Ltd | Administrative & support | 2015 |
| Complete Shield Limited | Wholesale & retail | 2020 |
| Complete Solutions Holdings Ltd | Financial services | 2021 |
| Complete Storage Solutions Ltd | Administrative & support | 2022 |
| Complete Transport UK Ltd | Transport & logistics | 2024 |
| Complete Wood Recycling Ltd | Water & waste | 2021 |
| Complicare Solutions Ltd | Administrative & support | 2025 |
| Conah W Boxing Ltd | Arts & recreation | 2025 |
| Conah Walker Merch Ltd | Wholesale & retail | 2026 |
| Concept Architectural Design Limited | Professional & scientific | 2016 |
| Concertive Engineering Holdings Ltd | Financial services | 2019 |
| Concertive Engineering Services Ltd | Construction | 2009 |
| Confiance Solutions Ltd | Health & social care | 2023 |
| Configure (UK) Limited | Construction | 2011 |
| Confuse the Machine Ltd | Information & communication | 2023 |
| Conoscenti Capital Limited | Real estate | 2020 |
| Conset Desks Limited | Wholesale & retail | 2021 |
| Consort Realty Limited | Other services | 2024 |
| Consta Global Limited | Wholesale & retail | 2025 |
| Construction Plant Flow Ltd | Wholesale & retail | 2019 |
| Consult Carrot Ltd | Professional & scientific | 2025 |
| Contactpilot Ltd | Information & communication | 2026 |
| Containers for Girls Limited | Extraterritorial | 2013 |
| Contessa Kitchens Limited | Construction | 2003 |
| Control and Automation Systems Limited | Manufacturing | 2018 |
| COOKING4CHAMPIONS Ltd | Hospitality | 2025 |
| Cooksey Reclamation Limited | Water & waste | 2002 |
| Cooksholme Management Company Limited | Households | 2023 |
| Coolspot Limited | Construction | 2003 |
| Coplastix Limited | Extraterritorial | 2023 |
| Copper Key Residential Ltd | Real estate | 2026 |
| Core Logic Parent Co Ltd | Financial services | 2026 |
| Corewave Tech Solutions Ltd | Information & communication | 2025 |
| Corinthians Catering Ltd | Hospitality | 2024 |
| Cornerstone Capital Holdings Ltd | Real estate | 2025 |
| Cornerstone Surveyors Limited | Professional & scientific | 2023 |
| Corvedale Education Limited | Agriculture & fishing | 2023 |
| Coscard Avenue Assisted Living Ltd | Health & social care | 2024 |
| Cosmic Star Ltd | Wholesale & retail | 2025 |
| COSMIC25 Ltd | Hospitality | 2025 |
| Costbuster Ltd | Wholesale & retail | 2025 |
| Cosy Keys Ltd | Real estate | 2024 |
| Cotwall Financial Planning Limited | Financial services | 2018 |
| Cotwall Place (Valley Road) Management Company Limited | Households | 2003 |
| Countrywide Management Solutions Ltd | Transport & logistics | 2026 |
| County Ground Care Holdings Ltd | Financial services | 2024 |
| County Ground Care Properties Ltd | Real estate | 2026 |
| Courage Health Care (West Midlands) Limited | Health & social care | 2010 |
| Courage Homes CIC | Real estate | 2024 |
| Courage Properties (West Midlands) Ltd | Real estate | 2024 |
| Courtenay Care Limited | Health & social care | 2023 |
| COX & Co (Dudley) Limited | Professional & scientific | 1992 |
| COX & Co Limited | Professional & scientific | 2013 |
| COX Hire Holdings Limited | Financial services | 2014 |
| COX Hire Limited | Administrative & support | 1948 |
| COX Homes Limited | Construction | 1964 |
| Coyot Auto Limited | Administrative & support | 2016 |
| Cozy Carpets & Flooring Ltd | Construction | 2025 |
| Cozy Tulips Estates Ltd | Real estate | 2024 |
| CP Mortgage Solutions Limited | Financial services | 2025 |
| CPC Vehicle Repairs Ltd | Wholesale & retail | 2024 |
| CPK Fabrications Limited | Construction | 2019 |
| CR Properties Midlands Limited | Real estate | 2025 |
| Craig Fletcher. Property Development & Letting Ltd | Construction | 2024 |
| Cravingspie Ltd | Administrative & support | 2019 |
| CRB Pro Contracts Ltd | Information & communication | 2024 |
| CRC Capital Ltd | Real estate | 2021 |
| CRE8 Investments Limited | Real estate | 2007 |
| Creart-Collective CIC | Health & social care | 2019 |
| Create Interiors and Fire Prevention Limited | Construction | 2022 |
| Create Seating Limited | Manufacturing | 2016 |
| Creative Day Nursery Group Limited | Education | 2025 |
| Creative Genie Ltd | Professional & scientific | 2024 |
| Creative Living by Michael Limited | Construction | 2015 |
| Crescita Limited | Financial services | 2025 |
| Cresswell Estates Limited | Professional & scientific | 2003 |
| Crestwood Motors (ENG.) Limited | Wholesale & retail | 1983 |
| Crja Freestone Holdings & Investments Ltd | Financial services | 2024 |
| Crja IT Consultancy Ltd | Information & communication | 2024 |
| Crja Property Ltd | Real estate | 2025 |
| CRL Property Limited | Real estate | 2023 |
| Cronexrabo Limited | Extraterritorial | 1982 |
| Crosswood Services Ltd | Administrative & support | 2025 |
| Crown Bar & Grill Ltd | Hospitality | 2016 |
| Crown Focus Limited | Health & social care | 2025 |
| Crowngold Limited | Real estate | 2016 |
| Crownpede Ltd | Administrative & support | 2018 |