| Connortech IT Limited | Administrative & support | 2025 |
| Conrad Young Limited | Professional & scientific | 2022 |
| Consignment Express Ltd | Transport & logistics | 2010 |
| Construct IT Systems Ltd | Information & communication | 2018 |
| Context Ridewear Ltd | Wholesale & retail | 2022 |
| Cool Waters Consulting Limited | Information & communication | 1999 |
| COR Christi Limited | Other services | 1995 |
| Corrigan Vintage Jewellery Ltd | Extraterritorial | 2019 |
| Corston Group Limited | Financial services | 2023 |
| Corston Ltd | Wholesale & retail | 2013 |
| Cotswold Engineering Limited | Manufacturing | 2019 |
| Cotswold Garden Restoration Specialist Ltd | Administrative & support | 2025 |
| Cotswold Holiday Lettings Limited | Real estate | 2014 |
| Cotswold Lakeside Developments Limited | Other services | 2022 |
| Cotswold Motors Ltd | Wholesale & retail | 2020 |
| Cotswold Party Ltd | Arts & recreation | 2017 |
| Cotswold Select Limited | Wholesale & retail | 2025 |
| Cotswold Speedshop Ltd | Wholesale & retail | 2021 |
| Cotswold Technix Ltd | Information & communication | 2023 |
| Cotswolds Wellbeing Ltd | Other services | 2026 |
| Country Style Taverns Limited | Hospitality | 1997 |
| Courtyard Clinic in Malmesbury Ltd | Health & social care | 2018 |
| Cowbridge Mill Sluice Gates Limited | Households | 2016 |
| COX Roofing and Construction Services Ltd | Construction | 2026 |
| CP Farming Ltd | Agriculture & fishing | 2019 |
| Craftmasters Gallery Ltd | Wholesale & retail | 2021 |
| Craig Fuller Property S&A Ltd | Real estate | 2012 |
| Creative Activist Ltd | Professional & scientific | 2011 |
| Creoda Consulting Limited | Professional & scientific | 2011 |
| Cresswell Finance Limited | Financial services | 2025 |
| Crichton HR Limited | Professional & scientific | 2013 |
| Crooked Cottage Computing Ltd | Information & communication | 1996 |
| Crosstrees Consulting Ltd | Professional & scientific | 2016 |
| Crudwell Garage Limited | Wholesale & retail | 2003 |
| Culver Advisory Limited | Professional & scientific | 2017 |
| Custom Transformers Limited | Manufacturing | 1972 |
| Cybercom Group Ltd | Professional & scientific | 2025 |
| D Morrison Limited | Other services | 2011 |
| D. & N.J. Freeth Ltd | Agriculture & fishing | 2012 |
| D.E.L Book Keeping Limited | Professional & scientific | 2009 |
| D.M.A. Developments Limited | Construction | 1981 |
| Dales Management Limited | Real estate | 2022 |
| Dalesco LLP | | 2023 |
| Dave Tyler Exhausts Limited | Manufacturing | 2002 |
| DCW Pubs Ltd | Hospitality | 2026 |
| Deirdre Dyson Carpets Ltd | Wholesale & retail | 2019 |
| Delafeld Holdings Limited | Financial services | 2025 |
| Delafeld Partners Limited | Professional & scientific | 2011 |
| DELIVERING4YOU Ltd | Administrative & support | 2022 |
| Dendri Robotics Ltd | Professional & scientific | 2023 |
| Design Drive Digital Ltd | Information & communication | 2025 |
| DHS Services Ltd | Agriculture & fishing | 2019 |
| Dhtconsultant (David Hunt Training Consultant) Limited | Professional & scientific | 2006 |
| Dickenson Design and Renovation Limited | Construction | 2021 |
| Digitune Ltd | Wholesale & retail | 2022 |
| Distiller Publishing LLP | | 2009 |
| Distiller Records LLP | | 2008 |
| DNC Enterprises Ltd | Professional & scientific | 2023 |
| Dodeca Design Ltd | Information & communication | 2021 |
| Dogtails and Dreams Ltd | Other services | 2022 |
| Double Diamond Dressage Ltd | Agriculture & fishing | 2023 |
| Double Diamond Stables Ltd | Agriculture & fishing | 2023 |
| DPE Autos Limited | Wholesale & retail | 2016 |
| DQD Engineering Ltd | Manufacturing | 2014 |
| DQD Holdings Limited | Financial services | 2024 |
| DQD Limited | Extraterritorial | 2024 |
| Dragonfly & Blossom Limited | Extraterritorial | 2019 |
| Drainmaster (Environmental) Limited | Other services | 2008 |
| Drainmaster (Wiltshire) Limited | Other services | 1997 |
| DST PM Services Ltd | Information & communication | 2022 |
| Dulnain Limited | Real estate | 2024 |
| Duncan Joyce & Associates Limited | Professional & scientific | 2012 |
| Dville Ltd | Professional & scientific | 2024 |
| Dynamic Support Housing Ltd | Households | 2024 |
| Dynamic Support Ltd | Health & social care | 2011 |
| Dyson Technical Training Limited | Education | 2017 |
| Dyson UK Group Limited | Manufacturing | 2009 |
| E.D.I. Technology Limited | Manufacturing | 2013 |
| Eastgate House Dental Surgery Limited | Health & social care | 2018 |
| Eastgate House Holdings Limited | Financial services | 2018 |
| Eaton House (Management) London Limited | Households | 2026 |
| Ecostock Ltd | Wholesale & retail | 2025 |
| Ecyou Limited | Manufacturing | 2021 |
| Eddison Cogan Lawyers Ltd | Professional & scientific | 2022 |
| Efficiency Health and Home Care Services Limited | Health & social care | 2015 |
| Egerton Consulting Ltd | Extraterritorial | 2001 |
| EKB Painting & Decorating Ltd | Construction | 2019 |
| Electrical & Electronic Services (Swindon) Limited | Manufacturing | 2003 |
| Elite Tutor Network Limited | Education | 2023 |
| Ellwood Limited | Households | 1991 |
| ELM Conveyancing Consultancy Limited | Professional & scientific | 2025 |
| Emerson Reloading Systems Ltd | Manufacturing | 2026 |
| Emma W Counselling Ltd | Health & social care | 2025 |
| Emmet Green Associates Limited | Administrative & support | 2000 |
| Enfilade Systems Limited | Information & communication | 2011 |
| Enganche Productions Ltd | Information & communication | 2019 |
| Engineering Acquisitions Limited | Financial services | 2023 |
| EPB Properties Limited | Real estate | 2008 |
| Essanbee Limited | Administrative & support | 2005 |
| Euancoker Limited | Wholesale & retail | 2022 |