| Home Farm Medical Limited | Health & social care | 2023 |
| Homegym UK Ltd | Real estate | 2009 |
| Homely Vision Ltd | Real estate | 2025 |
| Homes 4 U Aylesbury Ltd | Real estate | 2024 |
| Homewatt Limited | Wholesale & retail | 2008 |
| Hones Collection Ltd | Professional & scientific | 2025 |
| Honey Paws Dog Walking Ltd | Other services | 2022 |
| Honeybadger Law Limited | Professional & scientific | 2026 |
| Hook Norton Butchers Ltd | Manufacturing | 2013 |
| Horwin Ltd | Households | 2023 |
| Horwood Real Estate Services Limited | Professional & scientific | 2020 |
| Hot Chocolate Consultancy Limited | Administrative & support | 2013 |
| Howard Osborne Consulting Limited | Information & communication | 2017 |
| Hs-Ad Invest Limited | Financial services | 2021 |
| Hs-Ad Security Limited | Financial services | 2021 |
| HSD Consulting Ltd | Arts & recreation | 2023 |
| HSL Sunderland Ltd. | Extraterritorial | 2022 |
| HT Golf Coaching Ltd | Arts & recreation | 2026 |
| HTS (International) Ltd | Education | 1994 |
| Hudson Bays Limited | Professional & scientific | 1997 |
| HUM Lighting Limited | Wholesale & retail | 2026 |
| Human Capital Solutions International Ltd | Other services | 2020 |
| Hungry Head Ltd | Information & communication | 2019 |
| Huntsmill Farm LLP | | 2020 |
| Huntsmill Group Limited | Hospitality | 2024 |
| Hurst Food Management Ltd | Professional & scientific | 2024 |
| Husk Ventures Ltd | Administrative & support | 2023 |
| Hutch Carpentry Ltd | Construction | 2026 |
| Hyperion Thoroughbreds Ltd | Agriculture & fishing | 2021 |
| I & J Property Services Ltd | Construction | 2008 |
| I a J C Limited | Administrative & support | 2015 |
| I a L Consulting Limited | Professional & scientific | 2010 |
| I Teach Robotics Limited | Manufacturing | 2013 |
| I-Bodi Ltd | Professional & scientific | 2005 |
| I-Bodi Technology Limited | Manufacturing | 2007 |
| I4S Limited | Administrative & support | 2025 |
| IA Projects & Services Ltd | Information & communication | 2022 |
| Iain Borner Ltd | Information & communication | 2012 |
| IAL Ventures Ltd | Financial services | 2025 |
| IB Data Ltd | Professional & scientific | 2024 |
| IBS Building Specialists Ltd | Construction | 2025 |
| Ickokara Ltd | Construction | 2019 |
| Iconic Lifestyle Stays Limited | Real estate | 2026 |
| Icons Wall Art Ltd | Wholesale & retail | 2022 |
| Idatasource Limited | Information & communication | 2011 |
| Idle Retreats Ltd | Transport & logistics | 2018 |
| Iksectors Ltd | Wholesale & retail | 2025 |
| IL Bridges Holding Company Ltd | Financial services | 2024 |
| Ilter Ltd | Real estate | 2025 |
| IMD Cybersec Limited | Information & communication | 2024 |
| Immensity Healthcare Limited | Health & social care | 2023 |
| Imperium Sports Coaching Ltd | Arts & recreation | 2019 |
| Impetus Edge Limited | Information & communication | 2025 |
| IMS Design Ltd | Information & communication | 2023 |
| INA Truck Limited | Transport & logistics | 2020 |
| Increbidle Ltd | Professional & scientific | 2019 |
| Independent Access Sales Limited | Wholesale & retail | 2020 |
| Indexkey Limited | Information & communication | 1985 |
| Indian Iron Limited | Manufacturing | 2018 |
| Indian Threads Ltd | Wholesale & retail | 2018 |
| Indigo Technology Limited | Professional & scientific | 1999 |
| Inform Design & Development Limited | Professional & scientific | 2002 |
| Informatico Limited | Information & communication | 2025 |
| Inglesina Baby UK Limited | Wholesale & retail | 2026 |
| Ings & Associates Ltd | Financial services | 2020 |
| Inhouse Surveying and Architectural Design Limited | Professional & scientific | 2020 |
| Inkster Ltd | Wholesale & retail | 2024 |
| Innoflow Engineering Ltd | Professional & scientific | 2024 |
| Inntech Properties Ltd | Real estate | 2024 |
| Inntech Services Ltd | Information & communication | 2015 |
| Inovo Solutions Limited | Information & communication | 2016 |
| Inox Equip Limited | Manufacturing | 2000 |
| Insane Snacks Ltd | Wholesale & retail | 2025 |
| Insights Into Action Ltd | Professional & scientific | 2018 |
| Inspira Property Limited | Construction | 2011 |
| Inspire Cattle Solutions Ltd | Professional & scientific | 2018 |
| Inspires Dining Limited | Hospitality | 2020 |
| Institute for Free Trade Ltd | Professional & scientific | 2017 |
| Insulae Property Ltd | Real estate | 2020 |
| Insurtek Ltd | Information & communication | 2016 |
| Integrate IT Ltd. | Information & communication | 1998 |
| Intelligent Sales Networking Limited | Professional & scientific | 2013 |
| Inter Communication Services Ltd | Information & communication | 2020 |
| Interactive Stars Limited | Administrative & support | 2000 |
| Interactive Systems (Services) Ltd | Wholesale & retail | 2018 |
| International Gaming Solutions Limited | Other services | 2009 |
| Intrimotion Ltd | Professional & scientific | 2019 |
| Introvia Ltd | Professional & scientific | 2025 |
| Involved Events Ltd | Information & communication | 2013 |
| Ioar Holdings Limited | Other services | 2024 |
| Ioar Properties Limited | Real estate | 2025 |
| Iremote Coach Limited | Education | 2026 |
| Irig Computers Limited | Information & communication | 2017 |
| Iris Consultancy Limited | Information & communication | 2023 |
| Ironic Thought Ltd | Information & communication | 2010 |
| Ironing by the Professionals Limited | Other services | 2002 |
| Ironwood Advisory Group Ltd | Professional & scientific | 2025 |
| IRS Worldwide Limited | Public administration | 2020 |
| Irwin Industries Ltd | Financial services | 2023 |
| ISA Building Solutions Ltd | Construction | 2016 |