| Core Resolutions LLP | | 2009 |
| Core Strategies Solutions LLP | | 2026 |
| Core Study LAB LP | | 2014 |
| Coresq Ltd. | Professional & scientific | 1995 |
| Corglen Services Ltd | Construction | 2026 |
| CORINTHIAN6 Ltd | Wholesale & retail | 2026 |
| Corman Group LP | | 2019 |
| Cormargin Consulting Ltd | Information & communication | 2020 |
| Cormorant Consulting Services Ltd | Professional & scientific | 2018 |
| CORNER21 Ltd | Wholesale & retail | 2023 |
| Cornerstone Analytics Limited | Information & communication | 2010 |
| Cornerstone Church Watford | Other services | 2011 |
| Cornerstone Music Management Ltd | Arts & recreation | 2025 |
| Cornerstone Workforce Management Limited | Professional & scientific | 2025 |
| Corona Energy Retail 1 Limited | Energy | 1996 |
| Corona Energy Retail 3 Limited | Energy | 1992 |
| Corona Energy Retail 4 Limited | Energy | 1993 |
| Corona GAS Management Limited | Wholesale & retail | 1993 |
| Coronet Global Foods Ltd | Wholesale & retail | 2026 |
| Corporate Cleaning London Ltd | Administrative & support | 2026 |
| Corporate Financial Management Systems Limited | Information & communication | 2001 |
| Corra Decorators Ltd | Construction | 2022 |
| Corrinne Consulting Ltd | Real estate | 2012 |
| Corromat Consulting Limited | Administrative & support | 2012 |
| Corulca Solution Ltd | Manufacturing | 2025 |
| Corvena Co Ltd | Real estate | 2026 |
| COS Spedition Limited | Construction | 2024 |
| Cosentino Francesco Limited | Health & social care | 2016 |
| Coshell Trading Ltd | Wholesale & retail | 2020 |
| Cosmetic Remedies Ltd | Wholesale & retail | 2025 |
| Cosmi One Trans Ltd | Transport & logistics | 2016 |
| Cosmo Inventory Ltd | Real estate | 2015 |
| Cosmos Bidco Limited | Extraterritorial | 2020 |
| Cosmos Bruton Ltd | Real estate | 2021 |
| Cosmos EBT & Nominee Limited | Extraterritorial | 2020 |
| Cosmos Midco Limited | Extraterritorial | 2020 |
| Cosmos Topco Limited | Extraterritorial | 2020 |
| Cosol Consultants Ltd | Administrative & support | 2024 |
| Cospack (UK) Limited | Other services | 2002 |
| Costa Interiors Ltd | Construction | 2023 |
| Costataxi Ltd | Transport & logistics | 2025 |
| Costco Online UK Limited | Wholesale & retail | 2012 |
| Costco Travel UK Limited | Administrative & support | 2016 |
| Costco UK Holdings Limited | Wholesale & retail | 2000 |
| Costco Wholesale UK Limited | Wholesale & retail | 1991 |
| Costell Builders Ltd | Construction | 2026 |
| Cosworth Coastal Ltd | Real estate | 2026 |
| Cosworth Project Management Ltd | Construction | 2024 |
| Cosworth Ventures Ltd | Real estate | 2023 |
| Cosy Care CD Ltd | Health & social care | 2026 |
| Cosy Cave Limited | Construction | 2015 |
| Cosy Living CD Limited | Real estate | 2026 |
| Coukclya PIT Baltic Limited | Other services | 2010 |
| Coulsdon Properties Limited | Real estate | 2001 |
| Coulter Enterprises Ltd | Administrative & support | 2014 |
| Country Park Dental Practice Limited | Health & social care | 2006 |
| Courtgate Limited | Construction | 1978 |
| Courtlands Cafe Bistro Ltd | Hospitality | 2026 |
| Courtlands Drive Blocks "a & B" Management Company Limited | Households | 1991 |
| Courtlands Drive Blocks "C & D" Management Company Limited | Households | 1991 |
| Courtlands Food 2026 Ltd | Hospitality | 2026 |
| Courtlands Hill Ltd | Professional & scientific | 2022 |
| Courtlands Medical Ltd | Health & social care | 2016 |
| Courtlands Property Holdings Ltd | Real estate | 2016 |
| Cousins Brett LLP | | 2013 |
| Cousins Garage Ltd | Other services | 2010 |
| COV Salvage Ltd | Wholesale & retail | 2022 |
| Cove Connected Data Services Ltd | Professional & scientific | 2019 |
| Covent Garden Fishmongers Limited | Wholesale & retail | 2015 |
| Covidien UK Holding Ltd | Professional & scientific | 2008 |
| Covijn Ltd | Information & communication | 2016 |
| Cowcow Design Ltd | Wholesale & retail | 2020 |
| COX Automotive London Ltd | Wholesale & retail | 2026 |
| CP Analytics Ltd | Information & communication | 2016 |
| CP Consulting Ltd | Information & communication | 2020 |
| CP Holdings (Pensions) Limited | Professional & scientific | 1960 |
| CP Holdings Limited | Professional & scientific | 1957 |
| CP PAC Group Limited | Financial services | 2025 |
| CP Pharma Ltd | Wholesale & retail | 2019 |
| CP Regents Park Two Limited | Hospitality | 2004 |
| CP Retail (Trading) Ltd | Real estate | 2026 |
| CP Retail Group Ltd | Financial services | 2026 |
| CP Security Systems Limited | Administrative & support | 2017 |
| CP Tech Labs Ltd | Information & communication | 2025 |
| CPB GAS Ltd | Construction | 2023 |
| Cpbd Consultancy Ltd | Health & social care | 2022 |
| CPD Investment Limited | Real estate | 2016 |
| CPH 2024 Limited | Financial services | 2024 |
| CPL Homes Limited | Construction | 2015 |
| CPS Network Communications Ltd | Construction | 2014 |
| CPS Network Properties Ltd | Real estate | 2026 |
| CR Software Solutions Ltd | Information & communication | 2020 |
| Crackiton Ltd | Information & communication | 2026 |
| Craft Bakery Ltd | Manufacturing | 2024 |
| Craft Fair Ltd | Wholesale & retail | 2017 |
| Craft Programming Limited | Information & communication | 2018 |
| Crafted by Ceri Limited | Arts & recreation | 2022 |
| Crafted Leather Armour Ltd | Manufacturing | 2023 |
| Craftlock Developments Limited | Construction | 2026 |
| Crafty Crew Ltd | Transport & logistics | 2025 |