| Harper Investments Souldern | Financial services | 2021 |
| Harpoon Studios Ltd | Information & communication | 2024 |
| Hart Roofing Limited | Construction | 2007 |
| Hartley & London Ltd | Construction | 2018 |
| Harvest & Root Ltd | Wholesale & retail | 2025 |
| Harvest Systems Limited | Extraterritorial | 2024 |
| Harvey Design Engineering Ltd | Manufacturing | 2020 |
| Harvey&Sons Engineering&Fabrication Limited | Construction | 2014 |
| Hascombe Heath Limited | Hospitality | 2014 |
| Hascombe Land Limited | Real estate | 2019 |
| Hassan Property Services Limited | Real estate | 2020 |
| Havenhold Property Services Limited | Real estate | 2025 |
| Hawkes Sports Limited | Wholesale & retail | 2013 |
| Hawkins Employee Ownership Trustee Limited | Professional & scientific | 2024 |
| Hawkins Estates Limited | Construction | 2013 |
| Hawkins Projects Limited | Construction | 2011 |
| Hawkins Roofing Limited | Construction | 2011 |
| Hawkins Steel (UK) Ltd | Manufacturing | 2016 |
| Hawthorne Fire Consultancy Ltd | Public administration | 2023 |
| Haybridge Stud Ltd | Agriculture & fishing | 2021 |
| Hayes Property Renovations Ltd | Construction | 2013 |
| Haynes Strength Ltd | Arts & recreation | 2024 |
| Hazard Clean Ltd | Water & waste | 2025 |
| HBN Holdings Limited | Professional & scientific | 2018 |
| Hbpo UK Limited | Manufacturing | 2005 |
| Hbrown Ltd | Construction | 2024 |
| HCB Homes Ltd | Real estate | 2021 |
| HCB Mortgages Ltd | Financial services | 2017 |
| HCG Psychological Services Limited | Health & social care | 2017 |
| HCL Minibuses Ltd | Transport & logistics | 2023 |
| HD Project Management Ltd | Professional & scientific | 2019 |
| HDW Banbury Ltd | Wholesale & retail | 2009 |
| Headington Healthcare Ltd | Wholesale & retail | 2020 |
| Headline Digital Ltd | Professional & scientific | 2025 |
| Healsway Systems Solution Limited | Manufacturing | 2022 |
| Health Behaviour Research Consultancy Limited | Professional & scientific | 2015 |
| Health Informatics Services Ltd | Administrative & support | 2016 |
| Healthcare Evolution Ltd | Health & social care | 2020 |
| Hear Today Hear Tomorrow Ltd | Wholesale & retail | 2021 |
| Hearing AID Recycling Limited | Wholesale & retail | 2023 |
| Heath Catering Services Ltd | Hospitality | 2019 |
| Heath Windows, Doors & Conservatories Ltd | Construction | 2009 |
| Heating Solution Ltd | Construction | 2024 |
| Heaven Sent Ltd | Professional & scientific | 2015 |
| Heavolution Ltd | Wholesale & retail | 2021 |
| Hebe Studio Ltd | Professional & scientific | 2001 |
| Hedges Mobile Servicing & Repairs Ltd | Wholesale & retail | 2019 |
| Helicopter Club (G.B.) Limited | Other services | 1991 |
| Helix Autosport Limited | Manufacturing | 2004 |
| Hella Limited | Wholesale & retail | 1959 |
| Hella Manufacturing Limited | Extraterritorial | 1990 |
| Hella UK Holdings Limited | Professional & scientific | 1995 |
| Hello Street Ltd | Information & communication | 2020 |
| Hello Sweetpea Ltd | Wholesale & retail | 2026 |
| HELP4PROPERTYDEALS Limited | Real estate | 2023 |
| Helyar Robinson Ltd | Real estate | 2025 |
| Hendon Broadway Limited | Extraterritorial | 1995 |
| Henley Carpets and Flooring Limited | Wholesale & retail | 2013 |
| Hennell Partners Ltd | Financial services | 2025 |
| Henry & LO Limited | Other services | 2017 |
| HER Health Hub Coaching Ltd | Arts & recreation | 2024 |
| HER Word Ltd | Information & communication | 2025 |
| Hera Bloodstock Limited | Agriculture & fishing | 2021 |
| Herb Centre Limited | Wholesale & retail | 2008 |
| Heri-Tage Construction (UK) Ltd | Wholesale & retail | 2002 |
| Heritage Gate Residents Company Limited | Households | 1996 |
| Heritage Hunting Consultancy Limited | Agriculture & fishing | 2026 |
| Hermann Niesewand Ltd | Information & communication | 2007 |
| Hermex Trading Group Limited | Administrative & support | 2025 |
| Herobilla Ltd | Financial services | 2024 |
| Hertford Heath Limited | Hospitality | 2000 |
| Hertford Heath Realty Limited | Real estate | 2001 |
| Hespera Limited | Professional & scientific | 2006 |
| Hesperus Consultancy Services Limited | Professional & scientific | 2018 |
| Hewetson Investments Limited | Professional & scientific | 2008 |
| Hewetson LLP | | 2009 |
| Hexagon Gold Limited | Administrative & support | 2021 |
| HEY BWA Consulting Limited | Professional & scientific | 2024 |
| HEY Spud Ltd | Wholesale & retail | 2021 |
| Hf&Ms Limited | Information & communication | 2020 |
| HH BOW Limited | Extraterritorial | 2024 |
| HH Wapping Limited | Extraterritorial | 2024 |
| HHA Property and Investment Group Ltd | Real estate | 2023 |
| Hhac CIC | Health & social care | 2023 |
| Hhnl Solutions Limited | Professional & scientific | 2011 |
| HI Tech Finance Ltd | Financial services | 2019 |
| Hi-End Logistics Limited | Transport & logistics | 2024 |
| Hi-Tech Engineering Holdings (UK) Ltd | Wholesale & retail | 2017 |
| HI2 Limited | Information & communication | 1995 |
| Hicks Carpentry & Construction Ltd | Manufacturing | 2025 |
| Hicks Holdings Limited | Financial services | 2009 |
| Hidden Secret Ltd | Other services | 2016 |
| Hierarchy Ventures Limited | Real estate | 2016 |
| High Flyers Oxford Limited | Arts & recreation | 2013 |
| Hightown House Management Company Limited | Real estate | 2015 |
| Hillside Medical Supplies Limited | Wholesale & retail | 1991 |
| Himalayan Saltlamps Ltd | Professional & scientific | 2015 |
| Hinde-Smith Limited | Administrative & support | 2013 |
| Hippo Music Limited | Arts & recreation | 2005 |
| Hire Tech Ltd | Information & communication | 2025 |