| Coombs of Guildford Limited | Extraterritorial | 2011 |
| Coombs Performance Limited | Extraterritorial | 2014 |
| Coombs Racing Limited | Extraterritorial | 2007 |
| Coptoak Services Ltd | Information & communication | 2019 |
| Core CBS Holdings Ltd | Real estate | 2022 |
| Core CBS Limited | Professional & scientific | 2011 |
| Corporate Aero Mech Limited | Transport & logistics | 2013 |
| Cosma and Brothers Ltd | Wholesale & retail | 2025 |
| Costoff Ltd | Wholesale & retail | 2019 |
| Costsmaster Limited | Information & communication | 2001 |
| Covers Stevenage Ltd | Real estate | 2021 |
| COX 4 Limited | Construction | 2004 |
| COX Lewis Hearing Limited | Health & social care | 2022 |
| CPC Electrical Solutions Limited | Construction | 2005 |
| Craft Buddy Ltd | Wholesale & retail | 2010 |
| Craft Buddy Property Holdings Ltd | Real estate | 2023 |
| Craft Engineering Limited | Manufacturing | 1987 |
| Craftyard Events Limited | Hospitality | 2017 |
| Craftyard Ltd | Hospitality | 2022 |
| Craftyard Management Services Limited | Professional & scientific | 2021 |
| Craftyard PR Limited | Wholesale & retail | 2019 |
| Craftyard Tring Limited | Wholesale & retail | 2019 |
| Crag Path Capital Ltd | Professional & scientific | 2025 |
| Craig Philip Limited | Hospitality | 2024 |
| Create & Comply Limited | Professional & scientific | 2016 |
| Creative Corporate Clothing Ltd | Manufacturing | 2011 |
| Creative Cubs Limited | Health & social care | 2024 |
| Creative Mesh Limited | Information & communication | 2016 |
| Crescendo Strategy Ltd | Professional & scientific | 2025 |
| Crime Prevention Products Limited | Wholesale & retail | 2003 |
| Crow CR8 Ltd | Arts & recreation | 2025 |
| Crown Court ST. John's Wood Property Company Limited | Households | 1995 |
| Crown Taxis Limited | Transport & logistics | 2010 |
| Crowthorne Sports & Social Club Ltd | Hospitality | 2023 |
| Croxley Filming Company Limited | Other services | 2015 |
| Crystal Clear Accounting Solutions Limited | Professional & scientific | 2017 |
| Crystal Clear Business Consultants Ltd | Administrative & support | 2010 |
| Crystal Inventory Services Limited | Real estate | 2016 |
| CSW Real Estate Ltd | Real estate | 2025 |
| CT Builds Ltd | Wholesale & retail | 2025 |
| CT Medical Sales Limited | Wholesale & retail | 2020 |
| CTO4 Business Ltd | Information & communication | 2025 |
| CTR Restaurant Ltd | Hospitality | 2025 |
| Cube Cars Limited | Transport & logistics | 2017 |
| Culturerunner Limited | Professional & scientific | 2016 |
| Culwood House Limited | Health & social care | 2012 |
| Cups & Courage CIC | Information & communication | 2025 |
| Curb Appeal Property Staging Ltd | Professional & scientific | 2025 |
| Curly Radio Productions Ltd | Information & communication | 2013 |
| Custom Carpentry and Joinery Limited | Manufacturing | 2015 |
| Custom Restore Construction Limited | Construction | 2013 |
| Custom Restore Limited | Wholesale & retail | 2019 |
| CUT the Mustard Eardley RD Ltd | Hospitality | 2024 |
| CUT the Mustard Streatham High RD Ltd | Hospitality | 2024 |
| Cutforth Crew Limited | Information & communication | 2022 |
| D & K Care Limited | Health & social care | 2023 |
| D & M Heating and Plumbing Limited | Construction | 2006 |
| D J Barr and Kitchen Limited | Hospitality | 2020 |
| D M Smith & Sons Limited | Construction | 2003 |
| D S Mill Limited | Information & communication | 2015 |
| D V I Rental Limited | Real estate | 2017 |
| D&C Carpentry Chesham Ltd | Construction | 2024 |
| D&E Light Bites Ltd | Hospitality | 2024 |
| D&E Plumbing Ltd | Construction | 2025 |
| D'Orland KEG Limited | Administrative & support | 1993 |
| D7 Holdings Limited | Real estate | 2020 |
| D7 Trading Limited | Other services | 2020 |
| Daas Consultancy PVT Ltd | Information & communication | 2023 |
| Daffodil Facilities Management Limited | Administrative & support | 2019 |
| Dakiy Ltd | Real estate | 2016 |
| Danecker Structural Metal Fabrication Ltd | Manufacturing | 2011 |
| Daniel Hemsley Estates Ltd | Real estate | 2022 |
| Dark Grey Limited | Administrative & support | 1999 |
| Darvell 2228 RTE Company Limited | Households | 2003 |
| Darvells' & Sons Limited | Wholesale & retail | 2015 |
| Dash Payroll Consultancy Ltd | Professional & scientific | 2024 |
| Dashwood Studio Ltd | Professional & scientific | 2012 |
| Datarch UK Ltd | Information & communication | 2018 |
| David J Kirk Limited | Professional & scientific | 2017 |
| David J. Keogh Ltd | Education | 2023 |
| David R Saunders Limited | Professional & scientific | 2011 |
| David Trew Consulting Limited | Professional & scientific | 2013 |
| David Whiscombe LLP | | 2022 |
| Davina Kirby & Co. Limited | Professional & scientific | 2012 |
| Davis Smilescape Ltd | Health & social care | 2025 |
| Dayn Ltd | Administrative & support | 2018 |
| Dazzling Occasions Ltd | Professional & scientific | 2017 |
| DC Blanchard Ltd | Construction | 2017 |
| DCR Plumbing & Heating Limited | Construction | 2012 |
| DD Business Consulting Ltd | Professional & scientific | 2016 |
| DDK Trading Ltd | Wholesale & retail | 2025 |
| DDR Architects Limited | Professional & scientific | 2019 |
| DEA Systems Limited | Other services | 1994 |
| Debzac Limited | Professional & scientific | 2017 |
| Deer Park Walk Management Limited | Households | 1990 |
| Defacto GI76 Limited | Construction | 2017 |
| Definitive Audio Visual Limited | Professional & scientific | 2011 |
| Deft Studio Ltd | Professional & scientific | 2024 |
| Degat Consulting Ltd | Manufacturing | 2016 |
| Delta Partners LLP | | 2017 |