| Cluck 'N' Crisp Limited | Wholesale & retail | 2023 |
| Clue Healthcare Recruitment Ltd | Administrative & support | 2023 |
| Clyde & Langbourne Flat Management Company Limited | Households | 2000 |
| Clyde Millions Limited | Transport & logistics | 2017 |
| CM & HG Property LLP | | 2012 |
| CM Security Ltd | Administrative & support | 2012 |
| CMA Consulting (UK) Limited | Professional & scientific | 2015 |
| CMC Services (2017) Limited | Real estate | 2010 |
| Cmec Limited | Construction | 2025 |
| CMG Scaffolding Ltd | Construction | 2024 |
| CMI Demolition&Clearence Ltd | Construction | 2026 |
| Cmmw Limited | Hospitality | 2023 |
| CMP Homes Ltd | Real estate | 2023 |
| CMP Management Limited | Real estate | 2024 |
| Cnan Trade Ltd | Wholesale & retail | 2025 |
| CNG Consulting Services Ltd | Professional & scientific | 2021 |
| CNO Developments Limited | Real estate | 2011 |
| CNO Plastering Limited | Administrative & support | 2011 |
| Co-Parenting Matters Ltd | Health & social care | 2022 |
| Coach Hayward Ltd | Arts & recreation | 2020 |
| Coach House Mews (Redhill) Limited | Households | 1989 |
| Coaching 83 International Limited | Real estate | 2014 |
| Coal Trading & Utilities Limited | Administrative & support | 2009 |
| Coast & Capital Mortgages Limited | Financial services | 2016 |
| Coast & Capital Properties Limited | Real estate | 2021 |
| Coast Project Management Limited | Professional & scientific | 2016 |
| Coast Property Group Limited | Real estate | 2020 |
| Coastal Electrics Westgate Limited | Wholesale & retail | 2026 |
| COB Records Ltd | Information & communication | 2019 |
| Cobalt Aluminium Limited | Manufacturing | 2015 |
| Cobalt Construction PL Ltd | Construction | 2007 |
| Cobalt Developments PL Limited | Construction | 2015 |
| Cobalt Energy PL Ltd | Energy | 2019 |
| Cobalt Global Enterprises Ltd | Wholesale & retail | 2023 |
| Cobalt Management Limited | Households | 1995 |
| Cobham Close (Cippenham) Management Company Limited | Households | 1998 |
| Coco and NUT Coffee Westfield Ltd | Hospitality | 2025 |
| Coco Motorsport Limited | Arts & recreation | 2021 |
| Coco Solutions Limited | Health & social care | 2025 |
| Cocoa Jones Limited | Hospitality | 2017 |
| COD Masters Croydon Ltd | Hospitality | 2025 |
| Code Contractors UK Ltd | Construction | 2024 |
| Code MED Ltd | Information & communication | 2020 |
| Codez Solutions Limited | Information & communication | 2024 |
| Codingprogress Limited | Information & communication | 2025 |
| Codore Limited | Construction | 2023 |
| Coffee at the Stand Limited | Wholesale & retail | 2024 |
| Coffee Canonbury Ltd | Hospitality | 2021 |
| Coffee Music Ltd | Information & communication | 2015 |
| Coffee Organic Ltd | Wholesale & retail | 2024 |
| Cogniweave-Ai Ltd | Information & communication | 2025 |
| Cogpsych Limited | Administrative & support | 2003 |
| Cohen & Christopher Limited | Transport & logistics | 2000 |
| Cohen Development & Management Limited | Real estate | 2019 |
| Cohios Limited | Information & communication | 2025 |
| COI App Ltd | Financial services | 2018 |
| Coin and Crunch Ltd | Wholesale & retail | 2025 |
| Cokeham Court Tenants Associatio N (Worthing) Limited | Households | 1960 |
| Cold Customs Ltd | Wholesale & retail | 2026 |
| Coldest Creative Ltd | Information & communication | 2024 |
| Cole Industrial LP | | 2015 |
| Coleman Court Limited | Households | 1988 |
| Coles Contracts Limited | Manufacturing | 2015 |
| Colette Court RTM Company Limited | Households | 2006 |
| Colin Court Residents Company Limited | Households | 1992 |
| Colindale Gardens (NO.2) Residents Company Limited | Households | 1987 |
| Collabcreate Ltd | Information & communication | 2024 |
| Collabit Software Ltd | Information & communication | 2007 |
| COLLABOR8 Consulting Limited | Professional & scientific | 2024 |
| Collaborative Creations Ltd | Professional & scientific | 2021 |
| Collaku London Limited | Construction | 2024 |
| College Court Management (Ashburton) Limited | Households | 1983 |
| College Park Management (Bristol) Limited | Households | 2012 |
| Collenmore Construction Limited | Construction | 2013 |
| Colliers Court (Speedwell) Management Company Limited | Households | 2014 |
| Colliers Place Management Limited | Households | 2007 |
| Collingdale Lodge Freehold Limited | Households | 2004 |
| Collingham's Lettings Ltd | Real estate | 2018 |
| Collins 2017 Limited | Construction | 2017 |
| Collins Construction Ltd | Construction | 1956 |
| Collins Tech Limited | Information & communication | 2023 |
| Collison Place RTM Company Ltd | Households | 2015 |
| Colour Anodising Ltd | Manufacturing | 1938 |
| Colour of Research Limited | Other services | 2020 |
| Colson Bathrooms Limited | Construction | 2026 |
| Colvin Assured Leasing Limited | Professional & scientific | 1987 |
| Colvin Limited | Wholesale & retail | 1973 |
| Comaware Limited | Information & communication | 2020 |
| Combe Homes (Investments) Limited | Real estate | 2012 |
| Combined Financial Services Limited | Professional & scientific | 2006 |
| Comedy Lounge Limited | Arts & recreation | 2021 |
| Comet Sports Limited | Administrative & support | 2012 |
| Comeuppance Limited | Arts & recreation | 2001 |
| Comfort Care Recruitment and Training Limited | Health & social care | 2016 |
| Comfort-Wealth Ltd | Health & social care | 2024 |
| Comfortably Plumbed Ltd | Construction | 2014 |
| Comfortlink Care Ltd | Health & social care | 2025 |
| Comgo Crafts Ltd | Wholesale & retail | 2023 |
| Comind Intelligent Systems Limited | Information & communication | 2025 |
| Comint Solutions Ltd | Information & communication | 2014 |