| Cornwall Heating & Catering Ltd | Construction | 2023 |
| Corporate Advice & Solutions (UK) Ltd | Financial services | 2019 |
| Cottage Farm (Kirby) Ltd | Agriculture & fishing | 2013 |
| Coulter & Co (Accountants) Limited | Professional & scientific | 2003 |
| Council for Subject Associations Limited | Education | 2007 |
| Country Cat Sitters Limited | Agriculture & fishing | 2026 |
| Country Home Building Ltd | Construction | 2018 |
| Country Road Campers Ltd | Manufacturing | 2020 |
| Coupland Estates Limited | Real estate | 2025 |
| Coventry House Management Limited | Real estate | 1994 |
| CPI Consulting Limited | Professional & scientific | 2023 |
| Craggs Walk Developments Ltd | Construction | 2018 |
| Craig Oliver Homes Limited | Wholesale & retail | 1999 |
| Crane Express Holdings Limited | Financial services | 2020 |
| Crane Express Services Limited | Manufacturing | 1994 |
| Craneserve Limited | Manufacturing | 2012 |
| Cranwood Mortgage Services Limited | Financial services | 2008 |
| Craven Court (Melton) Management Limited | Administrative & support | 2011 |
| CRE8 Associates Limited | Professional & scientific | 2004 |
| Creative Golf Limited | Extraterritorial | 2003 |
| Crest Heritage Construction Ltd | Construction | 2026 |
| Criftin Enterprise Centre Limited | Administrative & support | 2020 |
| Croftway Limited | Professional & scientific | 2010 |
| Cromwell Insolvency (East Midlands) Ltd | Professional & scientific | 2018 |
| Crossfit Panic Ltd | Arts & recreation | 2015 |
| Crosston Estates Ltd | Construction | 2017 |
| Crown Bistro Limited | Hospitality | 2010 |
| Crown Windows & Doors Limited | Manufacturing | 2010 |
| Croxton Haulage Ltd | Transport & logistics | 2015 |
| Crump Media Limited | Administrative & support | 2005 |
| Cuberoot Energy Limited | Construction | 2009 |
| Cuberoot Ltd. | Information & communication | 2001 |
| Cura Care Online Limited | Financial services | 2009 |
| Cura Holdings Limited | Financial services | 2021 |
| Curemus Ltd | Health & social care | 2023 |
| Curios & Clobber Ltd | Wholesale & retail | 2016 |
| Curnaseer Limited | Agriculture & fishing | 1962 |
| Cyan Castle Ltd | Manufacturing | 2024 |
| CYBER23 Ltd | Information & communication | 2022 |
| Cytrome Ltd | Information & communication | 2016 |
| Czaplicki Transport Ltd | Transport & logistics | 2024 |
| D & J Wright (Plumbing & Heating Engineers) Ltd. | Construction | 2014 |
| D & N Services (Rutland) Ltd | Administrative & support | 2012 |
| D & P Homes Limited | Real estate | 2017 |
| D & S Bennett Holdings Limited | Financial services | 2021 |
| D & V Mccann Limited | Real estate | 2012 |
| D a Martin Associates Ltd | Construction | 2006 |
| D Eden Interiors Ltd | Construction | 2026 |
| D L James Ltd | Construction | 2023 |
| D&E House Clearances and Removals Ltd | Transport & logistics | 2025 |
| D.& R. Developments Limited | Real estate | 1988 |
| D.W.C.Engineering Limited | Professional & scientific | 2013 |
| D3 Investments Limited | Real estate | 2023 |
| DA & CW Property Services Ltd | Construction | 2012 |
| Dacxi Limited | Financial services | 2019 |
| Dalby Composites Limited | Manufacturing | 2023 |
| Damora BIO Limited | Professional & scientific | 2026 |
| DAN Aston Contracting Ltd | Construction | 2024 |
| DAN Bale Plastering Ltd | Construction | 2023 |
| Dandelion Farm (Smallholding) Limited | Agriculture & fishing | 2018 |
| Danpsych Limited | Health & social care | 2024 |
| Dapz Compound Audio Ltd | Information & communication | 2015 |
| Dartmeet Ltd | Administrative & support | 2025 |
| Dasani Property Services Ltd | Hospitality | 2012 |
| David Greaves Ltd | Administrative & support | 2012 |
| David Musson Fencing Limited | Wholesale & retail | 2002 |
| David W Rhodes Limited | Agriculture & fishing | 2015 |
| Davies Aviation Ltd | Manufacturing | 2025 |
| Davies Porter Media Ltd | Information & communication | 2020 |
| DBF16 Limited | Real estate | 2024 |
| DC Repossession Services Limited | Administrative & support | 2018 |
| DC Works Bespoke Garden Rooms Ltd | Manufacturing | 2026 |
| DCR Scaffolding Limited | Construction | 2007 |
| De-Struct Limited | Water & waste | 2020 |
| Dead Good PUB Company Limited | Hospitality | 2018 |
| Dealbatch Limited | Real estate | 1986 |
| Deben Farm Management Company Limited | Real estate | 2024 |
| Decentralised Trading Limited | Information & communication | 2026 |
| Deep Focus Ltd | Professional & scientific | 2020 |
| Defiant Solutions Ltd | Wholesale & retail | 2018 |
| Dendra Ltd | Health & social care | 2011 |
| Denella Ltd | Information & communication | 2024 |
| Derek Jones Butchers Ltd | Wholesale & retail | 2003 |
| Derek Shaw Racing Ltd | Arts & recreation | 2007 |
| Design and Planning Limited | Professional & scientific | 2015 |
| Design Check Limited | Professional & scientific | 2025 |
| Design Midlands Limited | Construction | 2002 |
| Dgsatech Limited | Professional & scientific | 2008 |
| DH1 Properties Limited | Real estate | 2016 |
| DHW Plastering and Building Services Ltd | Construction | 2022 |
| Dialysis Freedom CIC | Health & social care | 2009 |
| Diaphero Collective CIC | Professional & scientific | 2026 |
| Diaspora Energy Ltd | Professional & scientific | 2024 |
| Different Day Studio Limited | Manufacturing | 2024 |
| Different Gravy Finance Ltd | Professional & scientific | 2025 |
| Digital MON Ltd | Information & communication | 2024 |
| Digital Thread Limited | Professional & scientific | 2017 |
| DIM SUM Melton Limited | Hospitality | 2026 |
| Diners Choice Limited | Hospitality | 2024 |
| Direct Engineering & Contracting Ltd | Construction | 2022 |