| Dealflow AI Ltd | Information & communication | 2026 |
| Deerfield Retreat Limited | Hospitality | 2023 |
| Deja VU Creative Limited | Manufacturing | 2025 |
| Delta Refrigeration Limited | Manufacturing | 2025 |
| Design Nation Ltd | Manufacturing | 2022 |
| Designplus Cheminformatics Consultants Ltd | Professional & scientific | 2024 |
| Diane Archer Limited | Administrative & support | 2012 |
| Dickens Aviation Limited | Transport & logistics | 2001 |
| DJG Engineering Services Ltd | Construction | 2022 |
| DJM Removals Limited | Transport & logistics | 2021 |
| DJO Consulting Ltd | Information & communication | 2023 |
| Djpm Property Ltd | Real estate | 2018 |
| Dljb Services Ltd | Administrative & support | 2025 |
| DM Golf Tees Ltd | Wholesale & retail | 2025 |
| DMD Trading Limited | Administrative & support | 2013 |
| Dnl.Entertainment Limited | Information & communication | 2022 |
| Dodson Agricultural Limited | Agriculture & fishing | 2012 |
| Dodson Engineering Limited | Professional & scientific | 2022 |
| Dogfish-Hydrotherapy Limited | Other services | 2014 |
| Dooling Electrical Services Ltd | Wholesale & retail | 2022 |
| Dooling Property Ltd | Real estate | 2023 |
| Dorsett Consultants Limited | Professional & scientific | 2017 |
| Double Check Media Limited | Information & communication | 2015 |
| Doug Wood Associates Ltd. | Professional & scientific | 2014 |
| DPB Plastering Limited | Construction | 2006 |
| DR A.J. Amery and Associates Ltd | Health & social care | 2010 |
| Drawing Design Management Limited | Professional & scientific | 2003 |
| Dreki Ltd | Information & communication | 2013 |
| Drift Contract Services Ltd | Construction | 2016 |
| DRY Electric Limited | Construction | 2003 |
| Dun-Bri Group Limited | Financial services | 2025 |
| Dun-Bri Services Limited | Wholesale & retail | 2001 |
| Dzus Ltd | Wholesale & retail | 2026 |
| E.M. Gauge Society Limited(The) | Other services | 1985 |
| E.S.Noy and SON Limited | Agriculture & fishing | 1956 |
| Eagle EYE Flyovers Ltd | Information & communication | 2024 |
| Ealston Agencies Ltd | Wholesale & retail | 2016 |
| Earlington and Rose Ltd | Construction | 2025 |
| Earnside Energy Holdings Ltd | Financial services | 2018 |
| Earnside Energy Limited | Water & waste | 2010 |
| East Anglia Cardiology Ltd | Professional & scientific | 2008 |
| East Herts Citizens Advice Service | Administrative & support | 2000 |
| East Herts Golf Club Limited(The) | Arts & recreation | 1975 |
| East London Biogas Limited | Water & waste | 2011 |
| Eastmap Limited | Professional & scientific | 1986 |
| Eden Getaways Ltd | Administrative & support | 2018 |
| Electric Window Limited | Arts & recreation | 2006 |
| Electrical Renovations Ltd | Other services | 2021 |
| Electrick Media Ltd | Health & social care | 2024 |
| Elisabetta Cordaro Limited | Administrative & support | 2011 |
| Ellen Leslie Limited | Information & communication | 2011 |
| Elstree Helicopters Limited | Education | 2002 |
| EM & NM Creations Limited | Wholesale & retail | 2023 |
| Embrace Electrical Ltd | Construction | 2024 |
| Emerald Holdco Limited | Energy | 2019 |
| Emery Events Ltd | Construction | 2021 |
| Energen Biogas Holdco Ltd | Financial services | 2018 |
| Energon Solutions Limited | Wholesale & retail | 2009 |
| ENERGY4HERTS Limited | Professional & scientific | 2026 |
| Epic Leisure Tech Ltd | Manufacturing | 2020 |
| Equalis Accountancy & Taxation Ltd. | Information & communication | 2015 |
| Essentia Wellness Ltd | Arts & recreation | 2026 |
| Estate and Residence Management Limited | Households | 2022 |
| Evans & Wheeler Developments Limited | Construction | 2015 |
| Event Bookers Limited | Administrative & support | 2014 |
| EVO Flight Drone Specialists Ltd | Professional & scientific | 2022 |
| Evolution AGY Ltd | Professional & scientific | 2024 |
| Evolving Spaces Electrical Ltd | Construction | 2025 |
| Evolving Spaces Ltd | Construction | 2022 |
| Excelerater Solutions Limited | Information & communication | 2011 |
| EZ Cleans Exteriors Ltd | Administrative & support | 2025 |
| Facilipharma Ltd | Professional & scientific | 2023 |
| Fairoakes Limited | Professional & scientific | 2016 |
| Farmhouse RAW Ltd | Wholesale & retail | 2025 |
| Featherington Interiors Ltd | Professional & scientific | 2024 |
| Field Golf Limited | Arts & recreation | 2006 |
| Finally Software Limited | Information & communication | 2001 |
| Finesse UK Plumbing & Heating Ltd | Construction | 2021 |
| Finns.Inc Limited | Construction | 2024 |
| First Class Business Solutions Limited | Administrative & support | 1994 |
| Fish POT Productions Limited | Arts & recreation | 2001 |
| Fit Together Ltd | Arts & recreation | 2005 |
| Fitzjohn Consultants Limited | Professional & scientific | 2006 |
| Five Pull Ltd | Professional & scientific | 2025 |
| Flawless Flooring (UK) Limited | Professional & scientific | 2008 |
| Flint Essence Limited | Professional & scientific | 2026 |
| Flip Side C2C CIC | Health & social care | 2025 |
| FLR Cropdrying Limited | Extraterritorial | 2014 |
| FNM Consulting Ltd | Professional & scientific | 2024 |
| Forbes Douglas Ltd | Financial services | 2014 |
| Format Build Ltd | Real estate | 2021 |
| Format Designs Ltd | Professional & scientific | 2018 |
| Format Estates Ltd | Real estate | 2022 |
| Format Group Holdings Ltd | Professional & scientific | 2022 |
| Forum Connect Limited | Information & communication | 2008 |
| FOX Feeds Limited | Agriculture & fishing | 1985 |
| FOX Forages Limited | Agriculture & fishing | 2001 |
| FOY Fabrications Limited | Construction | 2014 |
| Franklin Sapsed Ltd | Real estate | 2010 |
| Fred the Printer Ltd | Manufacturing | 2006 |