| Hironai Ltd | Information & communication | 2025 |
| HJ Tenger (Newbury) Limited | Hospitality | 2018 |
| HK Interior Design Ltd | Wholesale & retail | 2023 |
| HK Residential Investments Ltd | Real estate | 2025 |
| HK Residential Ltd | Real estate | 2021 |
| HM Properties Solutions Limited | Financial services | 2024 |
| HNM Pro Limited | Professional & scientific | 2025 |
| Hobbs Property Services Ltd | Construction | 2015 |
| Hobbs Training Ltd | Professional & scientific | 2025 |
| Hobby Family Limited | Real estate | 2012 |
| Hold-On Productions UK ! Ltd | Professional & scientific | 2015 |
| Holdich Smith Ltd | Professional & scientific | 2011 |
| Holland House Books Ltd | Information & communication | 2021 |
| Holland Productions Ltd | Professional & scientific | 2021 |
| Hollie Parton Ltd | Wholesale & retail | 2021 |
| Holmes Sanderson Consulting Limited | Professional & scientific | 2017 |
| Holt Farm Ltd | Agriculture & fishing | 2026 |
| Holton Investments Limited | Financial services | 2020 |
| Home Architecture (UK) Ltd | Construction | 2013 |
| Home Farm Barns Committee Limited | Households | 2003 |
| Home Landing Ltd | Wholesale & retail | 2016 |
| Home-Start West Berkshire | Health & social care | 2005 |
| Homecare Staffing Solutions Ltd | Administrative & support | 2021 |
| Homelec Limited | Extraterritorial | 1991 |
| Honeycomb Developments Limited | Construction | 2024 |
| Hooked on Hair Limited | Other services | 2006 |
| Hopwood ASH Limited | Financial services | 2000 |
| Horizon Bloodstock Limited | Administrative & support | 2003 |
| Horizons Consulting Limited | Arts & recreation | 2008 |
| Horseman Coaches Limited | Transport & logistics | 1977 |
| Horsey Lightly LLP | | 2024 |
| Hoskins Electrical Services (H.E.S) Ltd | Construction | 2018 |
| Hostech Consulting Limited | Professional & scientific | 2014 |
| Hot News South Ltd | Wholesale & retail | 2023 |
| Hotetti Limited | Information & communication | 2011 |
| Hotsauce Design Works Limited | Professional & scientific | 2025 |
| Hotshot Henley Limited | Agriculture & fishing | 2023 |
| Hound Dog Investments Ltd | Real estate | 2012 |
| Houseofherbs Ltd | Wholesale & retail | 2023 |
| Housite Ltd | Wholesale & retail | 2025 |
| Houston Properties Limited | Construction | 2003 |
| HOW Electrical Services Limited | Construction | 2006 |
| Howard Court (Newbury) Ltd | Households | 1993 |
| Howard Electrical Services Ltd | Construction | 2009 |
| Howhigh Limited | Administrative & support | 2012 |
| HR Clarity Limited | Administrative & support | 2010 |
| HSL (Holdings) Limited | Administrative & support | 2008 |
| HSP Valves Group Limited | Wholesale & retail | 2004 |
| HSP Valves Holdings Limited | Wholesale & retail | 2022 |
| Htech Solutions Ltd | Financial services | 2022 |
| Hubba Limited | Water & waste | 2017 |
| Hudson Farms Limited | Wholesale & retail | 2022 |
| Hudson Raine Limited | Professional & scientific | 2006 |
| Hughes Bros. (Llanrwst & Trefriw) Limited | Transport & logistics | 1987 |
| Hughes Trading Co. (UK) Limited | Wholesale & retail | 2011 |
| Hugo Lewis Limited | Arts & recreation | 2017 |
| Hugo Palmer Limited | Arts & recreation | 2016 |
| Human Systems Integration Limited | Professional & scientific | 2011 |
| Humanis Limited | Professional & scientific | 2002 |
| Humanity Means Business Ltd | Professional & scientific | 2018 |
| Hummingbird Fibre Arts Ltd | Manufacturing | 2019 |
| Hundred Hills Limited | Extraterritorial | 2021 |
| Hungry Caterpillar Day Nurseries Limited | Administrative & support | 2000 |
| Hungry Skips Ltd | Administrative & support | 2022 |
| Huntley Group & SON Ltd | Administrative & support | 2023 |
| Hurdl Consultancy Ltd | Professional & scientific | 2026 |
| Hurdley & Company Limited | Professional & scientific | 2013 |
| Huscara Ltd | Manufacturing | 2017 |
| Husky Design Limited | Information & communication | 2013 |
| Hutchins Garden & Ground Maintenance Limited | Administrative & support | 2024 |
| Hutong Bureau Limited | Administrative & support | 2014 |
| Hutton Andover Limited | Construction | 2016 |
| HV Builders Limited | Construction | 2018 |
| HV Eyecare Ltd | Wholesale & retail | 2026 |
| HW Media Limited | Information & communication | 2021 |
| HX Fulfilment Ltd | Manufacturing | 2022 |
| HX Oxford Limited | Hospitality | 2023 |
| Hy-Tech Forming Systems (Euro) Limited | Manufacturing | 1990 |
| Hyde Park Village Nursery Limited | Education | 2014 |
| Hynes Davis Limited | Financial services | 1996 |
| Hypa Raithwaite LP | | 2010 |
| Hypersigns Limited | Professional & scientific | 2020 |
| Hyperwraps Limited | Other services | 2021 |
| I Turn Pages Ltd | Information & communication | 2026 |
| I-Gc Corporate Limited | Professional & scientific | 2015 |
| I-Migrate Ltd | Professional & scientific | 2022 |
| I-Motus LLP | | 2007 |
| I-Next Ltd. | Information & communication | 1995 |
| Iain Wallace Investments Limited | Information & communication | 2023 |
| IAN Collins Electrical Limited | Construction | 2002 |
| IAN Crossan Financial Services Limited | Financial services | 2015 |
| IAN Norman Architects Limited | Professional & scientific | 2015 |
| IAN Sanderson (Textiles) Limited | Wholesale & retail | 1967 |
| IB Architects Ltd | Professional & scientific | 2021 |
| Ibc-St. Peters Development Ltd | Construction | 2019 |
| Ice Marine Limited | Manufacturing | 1995 |
| Icomeco Limited | Information & communication | 2002 |
| Icon Ventures UK Ltd | Information & communication | 2022 |
| Icons Music Group Ltd | Information & communication | 2021 |
| ICS Computing Limited | | 1999 |