| Dmwr Architects Limited | Professional & scientific | 2013 |
| DO a Football Ltd | Information & communication | 2023 |
| Doctus Learning Ltd | Education | 2022 |
| Doorstep Cakes Ltd | Manufacturing | 2021 |
| DPC Contracts (London) Limited | Construction | 2011 |
| DPC Electrical Contracts Ltd | Construction | 2017 |
| DPC Mechanical Limited | Professional & scientific | 2018 |
| Dpltn Limited | Professional & scientific | 2026 |
| DRG Consulting Services Ltd | Professional & scientific | 2010 |
| DRK Pharma Solutions Ltd | Manufacturing | 2019 |
| Dunton Lodge Farm Limited | Agriculture & fishing | 2008 |
| DX Forum Limited | Administrative & support | 2017 |
| Earl & Greenly Cakes Limited | Manufacturing | 2013 |
| East Gate Lettings Limited | Real estate | 2023 |
| Ecopian Ltd | Manufacturing | 2026 |
| Eden Special Works Ltd | Construction | 2018 |
| Edge Campervans Limited | Manufacturing | 2019 |
| EGG Agency Limited | Professional & scientific | 2020 |
| Ektara Limited | Hospitality | 2019 |
| Elegant Events Ltd | Administrative & support | 2014 |
| Elroseonline Ltd | Wholesale & retail | 2024 |
| EMH Technology Limited | Information & communication | 2005 |
| Empower Limited | Professional & scientific | 1989 |
| EMS Lifts Limited | Other services | 2007 |
| Enchanted Garden Events Limited | Hospitality | 2019 |
| Enes Dogan Limited | Administrative & support | 2017 |
| Enni Investments Ltd | Hospitality | 2019 |
| EQT Consulting Services Ltd | Professional & scientific | 2022 |
| Erin Limited | Professional & scientific | 1995 |
| Essential Property (UK) LLP | | 2006 |
| Eurovettes Ltd | Professional & scientific | 1995 |
| Every Dog Club Baldock Ltd | Other services | 2025 |
| Every Little Film Ltd | Information & communication | 2007 |
| Extreme Capoeira Studios Limited | Professional & scientific | 2022 |
| Ez.Pz Works Ltd | Construction | 2026 |
| F&P Meats Limited | Wholesale & retail | 2016 |
| Fibrecreative Limited | Professional & scientific | 2025 |
| Film House Consulting Ltd | Professional & scientific | 2024 |
| Find a Part Ltd | Wholesale & retail | 2020 |
| Finest Frozen Food Ltd | Wholesale & retail | 2021 |
| FM Streamer Showdown Ltd | Information & communication | 2021 |
| Focus Properties Limited | Construction | 2001 |
| Focus Structural Limited | Construction | 2000 |
| Fore Good Investments Limited | Financial services | 2022 |
| Fuel Supply Solutions Limited | Administrative & support | 2012 |
| G D Building and Maintenance Services Limited | Construction | 2016 |
| G.S & S Inspections Limited | Other services | 2007 |
| G2 Packaging Limited | Administrative & support | 2020 |
| Gallery 1066 Fine Art Ltd | Administrative & support | 1999 |
| Garden City Packaging Limited | Administrative & support | 1976 |
| Gazebo Spare Parts Limited | Wholesale & retail | 2012 |
| Gemma DE Vecchi Limited | Arts & recreation | 2015 |
| Gentle Property & Construction Limited | Construction | 2024 |
| Geoghegan Bros. Limited | Construction | 1973 |
| Gilbert Shipley Ltd | Other services | 2026 |
| GMJ Solutions Ltd | Construction | 2026 |
| Gmuk Limited | Construction | 2016 |
| Golden Spur Enterprises Ltd. | Professional & scientific | 1999 |
| GPR GAS Service Ltd | Manufacturing | 2015 |
| Grabmaster Ltd | Other services | 2017 |
| Grade 1 Technology Limited | Wholesale & retail | 2022 |
| Grade a Beauty Limited | Other services | 2021 |
| Grade a Fashion Limited | Wholesale & retail | 2022 |
| Great Shelford Dental Surgery Limited | Health & social care | 2012 |
| Green Fish Consulting Ltd | Professional & scientific | 2021 |
| GTT Healthcare Ltd | Health & social care | 2025 |
| Guru Exam Prep Limited | Education | 2017 |
| GW Business Fit Ltd | Education | 2021 |
| GW Property Fit Ltd | Real estate | 2021 |
| Hameed KRD Ltd | Wholesale & retail | 2025 |
| Hamilton Billiards & Games Co Ltd | Manufacturing | 2003 |
| Hammond Consult Ltd | Real estate | 2022 |
| Hanrahan Limited | Construction | 2002 |
| Haria Holdings Limited | Financial services | 2019 |
| Hark Consultants Limited | Professional & scientific | 2023 |
| Hark Innovation Centre Limited | Information & communication | 2025 |
| Hark Wellbeing Limited | Other services | 2025 |
| Harlow Dental Surgery Limited | Health & social care | 2014 |
| Hartford Lake Fish Farm Limited | Agriculture & fishing | 2015 |
| Harveys Roofing Ltd | Construction | 2025 |
| Hazlewood FD Limited | Professional & scientific | 2022 |
| Head on Media Limited | Information & communication | 2008 |
| Heath Hall (Management) Limited | Households | 1975 |
| Helmore Industrial Water Treatment Ltd | Manufacturing | 2007 |
| Heraldry Society(The) | Other services | 1956 |
| Hertcabsgroup Ltd | Transport & logistics | 2025 |
| Hertfordshire Roofing Ltd | Construction | 2007 |
| Hertfordshire Windows Ltd | Construction | 2015 |
| Hesco Management Services Limited | Extraterritorial | 2015 |
| High Performance Metals Ltd | Wholesale & retail | 2017 |
| Higher Hanging Fruit Ltd | Professional & scientific | 2024 |
| Hill House Apartments Limited | Households | 2011 |
| Hinxwell Limited | Wholesale & retail | 2006 |
| Histon Dental Surgery Ltd. | Health & social care | 2015 |
| Hitchin Signs Limited | Administrative & support | 2020 |
| Hitchin Town Community Football Club Ltd | Arts & recreation | 2006 |
| HJB Casting Ltd | Arts & recreation | 2022 |
| HN Baldock Ltd | Hospitality | 2024 |
| HOL Property Ltd | Transport & logistics | 2023 |
| Holmes Marketing Limited | Professional & scientific | 2002 |