| Cowzinc Limited | Administrative & support | 2014 |
| Coyne Construction Solutions Ltd | Construction | 2026 |
| CPG Photography Limited | Professional & scientific | 2014 |
| CPK Consultancy Ltd | Other services | 2018 |
| CR Consultancy Solutions Ltd | Professional & scientific | 2024 |
| Cranborne Audio Limited | Manufacturing | 2017 |
| Cranborne Road Management Company Limited | Real estate | 2004 |
| Cranbourne Storage & Distribution Limited | | 1974 |
| Craniosacral Therapy Educational Trust | Other services | 2002 |
| Crawley Group Holdings Ltd | Real estate | 2025 |
| CRE8 Supported Living Ltd | Households | 2020 |
| Creamish Ltd | Manufacturing | 2021 |
| Create Housing Ltd | Real estate | 2026 |
| Createx Limited | Information & communication | 1997 |
| Creative Urban Real Estates Ltd | Real estate | 2011 |
| Credo Investments Limited | Financial services | 2000 |
| Crescent Building Solutions Limited | Construction | 2024 |
| Crescent London UK Ltd | Administrative & support | 2019 |
| Crest Master Properties Ltd | Construction | 2020 |
| Crest Motors Ltd | Wholesale & retail | 2009 |
| Crispwater Holdings Ltd | Administrative & support | 2026 |
| Critical Factors Limited | Professional & scientific | 2017 |
| Cronos Wellbeing Solutions Limited | Health & social care | 2023 |
| Crossbill Way RTM Company Limited | Households | 2019 |
| Crouch END Greens Ltd | Wholesale & retail | 2019 |
| Crowbar Construction Ltd | Construction | 2024 |
| Crown Hvac Limited | Construction | 2023 |
| Crownhill Building Services Ltd | Construction | 2023 |
| Crowns Property Ltd | Real estate | 2024 |
| Crownvale Estates Limited | Real estate | 2018 |
| CRR Corporate Consulting Limited | Administrative & support | 2025 |
| CRS Propco Limited | Real estate | 2025 |
| Crumbling the Antiseptic Beauty Limited | Professional & scientific | 2007 |
| Crystal Grey Limited | Hospitality | 2022 |
| Crystalclean&Co Ltd | Administrative & support | 2025 |
| Crystalov Ltd | Wholesale & retail | 2025 |
| Crystalov SVV Ltd | Wholesale & retail | 2025 |
| Cryvion Ltd | Information & communication | 2026 |
| CS1FITNESS Ltd | Other services | 2022 |
| CSB Lesotho Limited | Financial services | 2019 |
| CTI Electrical Limited | Construction | 2011 |
| Cuce Homes Ltd | Real estate | 2024 |
| Cucumber There and Then Limited | Extraterritorial | 2011 |
| Cuffley Dining Limited | Hospitality | 2025 |
| Cuffley Motor Company Limited | Wholesale & retail | 1977 |
| Cuffley Property Investments Limited | Real estate | 2013 |
| Cuffley Self Storage Ltd | Transport & logistics | 2026 |
| Cultivate Hair & Skin Ltd | Wholesale & retail | 2023 |
| Culture of Insight Limited | Professional & scientific | 2009 |
| Cumberland Flats Limited | Households | 2007 |
| Cumbrian Punk Limited | Arts & recreation | 2013 |
| Curated Engineering Limited | Administrative & support | 2024 |
| Curated Storage Limited | Wholesale & retail | 2024 |
| Cure Music International Limited | Arts & recreation | 2010 |
| Curerstuff Ltd | Arts & recreation | 2010 |
| Curious Minds Nursery Ltd | Education | 2020 |
| Curo Support Services Limited | Administrative & support | 2008 |
| Custom Build Homes Limited | Construction | 2012 |
| Cutahurst Limited | Wholesale & retail | 1976 |
| CW Consulting Limited | Professional & scientific | 2005 |
| CWG Bespoke Ltd | Construction | 2020 |
| Cyber Strategies Ltd | Information & communication | 1998 |
| Cygnet Heating Limited | Administrative & support | 2009 |
| D & F Polishing Limited | Administrative & support | 2002 |
| D & H Technical Services Limited | Professional & scientific | 2009 |
| D & O Bistro Ltd | Hospitality | 2026 |
| D a Tippers Ltd | Water & waste | 2025 |
| D Bird Carpentry and Building Ltd | Manufacturing | 2021 |
| D Holwerda Cleaning Limited | Administrative & support | 2011 |
| D M Accounting Ltd | Professional & scientific | 2002 |
| D Pappas Construct Ltd | Construction | 2018 |
| D Pro Construction Limited | Construction | 2004 |
| D&B Medical Consultancy Ltd | Professional & scientific | 2021 |
| D&E Williams Property Services Ltd | Real estate | 2026 |
| D.Mccarroll Ltd | Construction | 2021 |
| D.S. Energy Limited | Construction | 2015 |
| D20 Properties Limited | Real estate | 2024 |
| D2H London Clothing Ltd | Wholesale & retail | 2019 |
| D8 Tickets Limited | Professional & scientific | 2019 |
| Dada Designs Ltd | Manufacturing | 2012 |
| Dadoan Ltd | Professional & scientific | 2024 |
| Daidegas Ltd | Administrative & support | 2012 |
| DAK Technologies Limited | Information & communication | 2016 |
| Dale Aviation and Compliance Ltd. | Professional & scientific | 2013 |
| Dame Alice Owen's School | Education | 2011 |
| Damelle Holdings Limited | Financial services | 2025 |
| Damprotek Supplies Limited | Construction | 2010 |
| Damsel Properties Limited | Real estate | 2008 |
| DAN Townsend Cabinetry Limited | Manufacturing | 2026 |
| Dance Explorers Ltd | Arts & recreation | 2024 |
| Daniel Field Retail Ltd | Wholesale & retail | 2020 |
| Danisautodetailing Limited | Administrative & support | 2025 |
| Daniva Ltd | Health & social care | 2025 |
| Danny a Ltd | Construction | 2017 |
| Dapsol Limited | Education | 2021 |
| DAR Hair & Beauty Ltd | Other services | 2016 |
| Dara Knot Wellness Limited | Hospitality | 2023 |
| Darkes Catering Ltd | Hospitality | 2025 |
| Darling Properties Limited | Real estate | 2002 |
| Daro Associates Limited | Administrative & support | 2004 |