| Customer Xperience Alliance Limited | Administrative & support | 2026 |
| Cybele Developments Limited | Construction | 2009 |
| Cyclists Fighting Cancer | Other services | 2010 |
| Cygnet Administration Limited | Professional & scientific | 2019 |
| D F Lynch Limited | Professional & scientific | 2016 |
| D K K Promotions Ltd | Professional & scientific | 2024 |
| D M Perry Construction Limited | Construction | 2013 |
| D Property Management Ltd | Real estate | 2024 |
| D W Clark (Drainage) Limited | Construction | 1990 |
| D&D Group International Ltd | Administrative & support | 2015 |
| D&J Electrical Ltd | Construction | 2018 |
| D-Viant Hair Limited | Other services | 2012 |
| DA Health and Performance Limited | Other services | 2024 |
| Daisy Training Limited | Professional & scientific | 2002 |
| Daisy Violet Ltd | Hospitality | 2023 |
| Dalim Software UK Limited | Information & communication | 2020 |
| Daltons Plastering Limited | Construction | 2003 |
| Dana Holdings Limited | Professional & scientific | 1978 |
| Dana Investments UK Limited | Financial services | 2002 |
| Dana Limited | Professional & scientific | 2018 |
| Dana Spicer Europe Limited | Manufacturing | 1949 |
| Dana UK Automotive Systems Limited | Administrative & support | 2007 |
| Dana UK Axle Limited | Administrative & support | 2007 |
| Dark Frontier Games Ltd | Professional & scientific | 2018 |
| Data Strategists Ltd | Professional & scientific | 2005 |
| Dave Hill (Music) Limited | Arts & recreation | 1981 |
| Davent Consultancy Services Ltd | Professional & scientific | 2023 |
| David Bruce Eggs Limited | Wholesale & retail | 2010 |
| David Cranage Developments Ltd | Real estate | 2015 |
| David Howell Wealth Management Ltd | Financial services | 2020 |
| David Lawrance Art Ltd | Arts & recreation | 2026 |
| Dawn Lodge Associates Limited | Professional & scientific | 2003 |
| Dawn Ventures Limited | Administrative & support | 2012 |
| Dawson Technologies Ltd | Professional & scientific | 2023 |
| DAX Bison Ltd | Professional & scientific | 2019 |
| Day Lewis Planning Ltd | Professional & scientific | 2011 |
| Daytona Consulting Ltd | Hospitality | 2024 |
| DBD Loxley Limited | Professional & scientific | 2013 |
| DCA Projects Limited | Construction | 2016 |
| Dcwt Media Limited | Information & communication | 2020 |
| DD Hills Hospitality Ltd | Hospitality | 2023 |
| DE Bono Marketing Communications Limited | Professional & scientific | 2016 |
| DE Coveney Limited | Professional & scientific | 2012 |
| DE Jong Academy Ltd | Education | 2022 |
| Dead-On Electrical Ltd | Construction | 2021 |
| Deadly Rhythm Limited | Information & communication | 2011 |
| Deam Consulting Ltd | Professional & scientific | 2015 |
| Deco P&D Ltd | Construction | 2014 |
| Deecie Art Ltd | Professional & scientific | 2025 |
| Deep Clear Technologies Ltd | Information & communication | 2023 |
| Deep Dive AI Technology Limited | Information & communication | 2017 |
| Deep Dive Data Technologies Limited | Information & communication | 2023 |
| Deepgreen Consultancy Ltd | Professional & scientific | 2024 |
| Deline UK Ltd | Information & communication | 2007 |
| Delta Analytics Training Ltd | Education | 2021 |
| Denial Limited | Professional & scientific | 2019 |
| Dennis&Crosscatering Ltd | Hospitality | 2023 |
| Denson Ltd | Wholesale & retail | 2017 |
| Denville Interiors Limited | Construction | 2015 |
| Derwent Court Management (Warwick) Limited | Households | 1977 |
| Design by Nurture Ltd | Professional & scientific | 2023 |
| Design Penguin Creative Ltd | Information & communication | 2017 |
| Design Visual Limited | Professional & scientific | 2008 |
| Desktop Genetics Ltd | Information & communication | 2012 |
| Desresdesign Limited | Professional & scientific | 2010 |
| Destination Motorhomes Limited | Wholesale & retail | 2010 |
| Developing Active Young Minds Ltd | Public administration | 2021 |
| DFT Ltd | Health & social care | 2025 |
| DG Electrical Services (Warwickshire) Limited | Construction | 2023 |
| DGR Electrical Ltd | Construction | 2022 |
| Dhaliwal Dentistry Limited | Health & social care | 2019 |
| DHM Wynchwood LLP | | 2011 |
| Diamond Caravans Limited | Wholesale & retail | 2013 |
| Diamond Electrical Installations Ltd | Construction | 2019 |
| Diamond Sports Coaching Ltd | Education | 2018 |
| Diddly Pixels Ltd | Manufacturing | 2025 |
| Digifreight Ltd | Other services | 2020 |
| Digital Accounts and Tax Support Ltd | Professional & scientific | 2017 |
| Digitiser Limited | Professional & scientific | 2022 |
| Dino Solutions Ltd | Wholesale & retail | 2018 |
| Direct Supply Solutions Ltd | Wholesale & retail | 2023 |
| Discovery Camera Systems Limited | Manufacturing | 2015 |
| Display-Tech Ltd | Wholesale & retail | 2015 |
| Distinctive People HR & OD Consultancy Limited | Administrative & support | 2015 |
| DJ Jeffreys Ltd | Arts & recreation | 2018 |
| DJM Cotswold Properties Ltd | Real estate | 2021 |
| DJM Tools and Industrial Supplies Limited | Manufacturing | 2002 |
| DK Farms Limited | Agriculture & fishing | 2015 |
| DKM Creative Limited | Administrative & support | 2020 |
| DLJ Accountancy Solutions Limited | Professional & scientific | 2009 |
| DLX Ltd | Construction | 2017 |
| DM 2024 Limited | Real estate | 2024 |
| DM Dental Solutions Limited | Health & social care | 2024 |
| Dobson-Grey Ltd | Real estate | 2008 |
| Document Insights Limited | Information & communication | 2014 |
| Dog Green Insights Ltd | Information & communication | 2019 |
| Domino Style Limited | Wholesale & retail | 2001 |
| Domoney Productions Limited | Arts & recreation | 2024 |
| DON David EYE Care Limited | Health & social care | 2011 |
| Donna Savage Planning Limited | Professional & scientific | 2007 |