| Hertfordshire Property Management Ltd | Real estate | 2024 |
| Herts & Beds Transmission Limited | Wholesale & retail | 1998 |
| Herts Associates Limited | Professional & scientific | 2020 |
| Herts Carpet Clean and Services Limited Ltd | Administrative & support | 2026 |
| Herts Communications Limited | Professional & scientific | 2018 |
| Herts Doors Ltd | Construction | 2026 |
| Herts Flooring and Interiors Ltd | Wholesale & retail | 2011 |
| Herts Flooring Limited | Extraterritorial | 2014 |
| Herts Pro Tiling Ltd | Construction | 2018 |
| Herts Properties and Management Ltd | Real estate | 2022 |
| Herts Security Systems Ltd | Administrative & support | 2018 |
| Herts Supreme Roofing Services Ltd | Construction | 2023 |
| Herts Tree Surgeons Ltd | Administrative & support | 2012 |
| Herts Used Cars Ltd | Wholesale & retail | 2018 |
| Herts Wraps Ltd | Construction | 2020 |
| Hertsgas Ltd | Wholesale & retail | 2025 |
| Hertsgk Ltd | Education | 2025 |
| Hertsone Ltd | Health & social care | 2017 |
| Herut UK Limited | Education | 2020 |
| Hesslewood Park Management Company Limited | Households | 2020 |
| Heston Management Limited | Construction | 2014 |
| Heylal Ltd | Manufacturing | 2026 |
| Heythrop Park Limited | Hospitality | 1999 |
| Heyu Ltd | Transport & logistics | 2022 |
| HGL Removals Ltd | Transport & logistics | 2025 |
| HH Boxing and Fitness CIC | Health & social care | 2026 |
| HH Consulting Limited | Professional & scientific | 2021 |
| HH Drivers Ltd | Transport & logistics | 2018 |
| Hh-Trampolining Limited | Administrative & support | 2024 |
| Hi-Vis Developments Ltd | Construction | 2026 |
| Hieta Technologies Ltd | Manufacturing | 2011 |
| High 10 Events Ltd | Arts & recreation | 2025 |
| High Forest (New Waltham) Management Company Limited | Households | 2023 |
| High Ridge Consulting Limited | Construction | 2009 |
| High Sense Securities Limited | Real estate | 1989 |
| High Street (Flore) Management Company Limited | Households | 2016 |
| HIGH5 Designs Ltd | Professional & scientific | 2024 |
| Highbury New Park Management Limited | Households | 2015 |
| Highcrest Limited | Real estate | 2026 |
| Highcroft Landscapes Limited | Administrative & support | 2009 |
| Highdale Fold Management Company Limited | Households | 2006 |
| Highfields Management Company (Chester-Le-Street) Ltd | Households | 2004 |
| Highlands Grange Management Company Limited | Households | 2023 |
| Highlight Resources Limited | Health & social care | 2015 |
| Highline Conversions Ltd | Wholesale & retail | 2024 |
| Highline Solicitors Limited | Professional & scientific | 2016 |
| Highrisk Limited | Information & communication | 2024 |
| Highstepper Limited | Wholesale & retail | 2023 |
| Highwalls Consulting Ltd | Financial services | 2016 |
| Highways Drone Services Ltd | Professional & scientific | 2025 |
| HIJ4CK Eventz Ltd | Professional & scientific | 2024 |
| Hillcrest Estate Management Limited | Real estate | 1985 |
| Hillfield Arel Ltd | Real estate | 2024 |
| Hillfoot Court Management Company Limited | Households | 2003 |
| Hilllow Group Limited | Households | 2026 |
| Hillmeadow View Management Company Limited | Households | 2012 |
| Hillside Park Norton (Management Company) Limited | Households | 2007 |
| Hiloka Limited | Information & communication | 2007 |
| Hilone Medical Limited | Health & social care | 2017 |
| Hiltfalcon Limited | Real estate | 1985 |
| HIMANDI2021 Limited | Hospitality | 2025 |
| Himanyu Technologies Limited | Information & communication | 2013 |
| Himspiration Concepts Limited | Manufacturing | 2007 |
| Hinds Media Ltd | Information & communication | 2022 |
| Hines & Hopkins Ltd | Administrative & support | 2010 |
| Hippertech Ltd | Wholesale & retail | 2020 |
| Hisaabun Ltd | Professional & scientific | 2024 |
| HJ Alignment Limited | Information & communication | 2025 |
| HJM Projects Ltd | Wholesale & retail | 2025 |
| HJM Typing Limited | Administrative & support | 2022 |
| HK Cyber Solutions Limited | Administrative & support | 2019 |
| Hkiu Limited | Financial services | 2015 |
| HL Harren Ltd | Construction | 2023 |
| HLM Group Ltd | Financial services | 2016 |
| HLM Locum Services Limited | Health & social care | 2024 |
| HML Building Services Ltd | Construction | 2016 |
| HMM Logistics Ltd | Transport & logistics | 2018 |
| Hnosi Space Solutions Ltd | Administrative & support | 2024 |
| Hobbs Cleaning Limited | Administrative & support | 2015 |
| Hobbs Electrical Group Ltd | Construction | 2026 |
| Hobdens Property Management Limited | Households | 2000 |
| Hoff Designs Limited | Arts & recreation | 2025 |
| Hogans Hounds Ltd | Transport & logistics | 2025 |
| Holbec Ltd | Professional & scientific | 2022 |
| Holding Builders Ltd | Construction | 2025 |
| Holding Cleaners Ltd | Administrative & support | 2021 |
| Holding Scaffolding Ltd | Construction | 2024 |
| Holding Solutions Group Ltd | Construction | 2025 |
| Holford Properties Ltd | Real estate | 2025 |
| Holford Surveying Ltd | Professional & scientific | 2023 |
| Holiday Park Holdings Limited | Hospitality | 2008 |
| Holistic Medicare Limited | Wholesale & retail | 2010 |
| Holivans Limited | Hospitality | 1951 |
| Holland Park Trading Ltd | Wholesale & retail | 2024 |
| Hollingsworth Pack Ltd | Professional & scientific | 2023 |
| Holly Bush Court Midsummer Meadow Management Company Limited | Households | 2024 |
| Holly Court (Garston) Management Company Limited | Households | 2005 |
| Hollyhill Advisory Ltd | Professional & scientific | 2023 |
| Hollytree Walk (Colchester) Management Company Limited | Real estate | 2020 |
| Hollywood Bowl EBT Limited | Professional & scientific | 2016 |