| Haven LUX Property Interiors Limited | Professional & scientific | 2025 |
| Hawthorns (Bournemouth) Management Limited | Households | 2003 |
| Haynes and Company (Sherington) Limited | Real estate | 1942 |
| HCI 2025 CIC | Real estate | 2025 |
| Hcsb Capital Ltd | Real estate | 2023 |
| Heal Wellness Ltd | Hospitality | 2024 |
| Healthier Homes Ltd | Construction | 2020 |
| Hearth and Hammer Ltd | Construction | 2026 |
| Hearth and Home Chimneys Limited | Construction | 2014 |
| Hefferon Heating Ltd | Construction | 2017 |
| Heiber Schroeder ( UK ) Limited | Administrative & support | 2015 |
| Hekima Ltd | Health & social care | 2019 |
| Henceforth Ltd | Other services | 2021 |
| Henderson Holdings (Northampton) Limited | Financial services | 2024 |
| Henry Devas Ltd | Other services | 2023 |
| Heritage Cards & Collectables Limited | Wholesale & retail | 2025 |
| Hermes Forensic Solutions Limited | Administrative & support | 2009 |
| Hestmare Properties Ltd | Real estate | 2022 |
| Hickleton Hall Heritage Centre Limited | Administrative & support | 2018 |
| Hickleton Hall Limited | Administrative & support | 2021 |
| Hickling Service Area Limited | Real estate | 2019 |
| Higgs Plumbing and Heating Limited | Construction | 2009 |
| Hills Carpentry & Construction Ltd | Manufacturing | 2025 |
| Hinds Blinds Limited | Professional & scientific | 2015 |
| Hireharbour Ltd | Administrative & support | 2023 |
| Hkam Limited | Real estate | 2021 |
| Hola Internet Limited | Information & communication | 2020 |
| Hole Sale Golf Ltd | Wholesale & retail | 2023 |
| Holy COW Takeaway Limited | Hospitality | 2024 |
| Home to Home Exchange Limited | Administrative & support | 2018 |
| Homeholder Limited | Real estate | 2014 |
| Homes on Web Ltd | Real estate | 2014 |
| Hoofco Ltd | Extraterritorial | 2014 |
| Hopefulwigs Ltd | Other services | 2025 |
| Horizon Exclusive Ltd | Wholesale & retail | 2023 |
| Horner Recruitment Limited | Administrative & support | 2008 |
| Hospitality Tech Solutions Ltd | Information & communication | 2017 |
| Hostas (UK) Limited | Administrative & support | 2011 |
| Howard Cafe Bedford Limited | Hospitality | 2015 |
| Howard Industries Limited | Extraterritorial | 1986 |
| Hoyte Transport Limited | Transport & logistics | 2019 |
| HUE Strategic Solutions Limited | Information & communication | 2025 |
| Hughes Technical Solutions Limited | Professional & scientific | 2009 |
| Huguenot Terrace Residents Association Limited | Real estate | 1999 |
| HUT-3 Limited | Administrative & support | 2017 |
| Hybrid Health Personal Training Ltd | Arts & recreation | 2026 |
| Hybridcleaningsolutions Ltd | Administrative & support | 2023 |
| Hygienic Interiors Ltd | Professional & scientific | 2007 |
| Hygienic Wall Cladding Limited | Wholesale & retail | 2011 |
| Hyper 4 Limited | Professional & scientific | 2015 |
| Hypervsm Ltd | Information & communication | 2025 |
| I. G. Employee Share Trustee Limited | Extraterritorial | 1998 |
| I.B. Electronics Limited | Wholesale & retail | 2003 |
| I.T. Solutions - Newport Pagnell Ltd | Information & communication | 2020 |
| IAN J Hawkins Ltd | Information & communication | 2013 |
| Ibell Recruitment & Staffing Ltd | Administrative & support | 2016 |
| Icece Limited | Extraterritorial | 2017 |
| Idesigndigital Limited | Information & communication | 2015 |
| IF Consultants Limited | Professional & scientific | 2006 |
| IF Dwellings LLP | | 2019 |
| IF Housing Limited | Real estate | 2017 |
| IG Design Group Holdings Limited | Professional & scientific | 1998 |
| IG Design Group PLC | Professional & scientific | 1978 |
| IG Design Group UK Limited | Manufacturing | 1988 |
| IJH Property Renovation Limited | Real estate | 2023 |
| IKR Pest Control Ltd | Administrative & support | 2024 |
| Imjgroup Ltd | Information & communication | 2021 |
| Imlugo Limited | Real estate | 2018 |
| Imnas Health Ltd | Information & communication | 2023 |
| Impedance Electrical Limited | Construction | 2013 |
| Imperial Hospitality Management Ltd | Hospitality | 2022 |
| Imperial Rise Developments Ltd | Construction | 2026 |
| Improvement Partnership Ltd | Professional & scientific | 2010 |
| Inclusion.Me Limited | Administrative & support | 2009 |
| Indian Curry Khana Ltd | Hospitality | 2022 |
| Indigo Marble Ltd | Wholesale & retail | 2016 |
| Indracas Limited | Professional & scientific | 2015 |
| Indraft Solutions Limited | Administrative & support | 2002 |
| Induspray Ltd | Construction | 2022 |
| Inferrix Limited | Manufacturing | 2016 |
| Ingles Tax and Training Ltd | Professional & scientific | 2001 |
| Inova Online Ltd | Manufacturing | 2014 |
| Insite Web Limited | Professional & scientific | 2013 |
| Inspire Travel Ltd | Administrative & support | 2025 |
| Inspired Estate Agents Ltd | Real estate | 2010 |
| Inspired Lettings (MK) Ltd | Real estate | 2016 |
| Inspired Property Sourcing Ltd | Construction | 2022 |
| Inspired Sales & Lettings Ltd | Real estate | 2012 |
| Inspiring Ventures Ltd | Financial services | 2022 |
| Instrom Ltd | Administrative & support | 1998 |
| Integrasol Limited | Construction | 2010 |
| Interdirect Marketing Limited | Extraterritorial | 2012 |
| Interesting Audio Visual Limited | Administrative & support | 2010 |
| International Media Solutions Ltd | Wholesale & retail | 2024 |
| International Parcel Experts Limited | Transport & logistics | 2025 |
| International Tank Leasing Ltd | Transport & logistics | 2017 |
| Ippso Limited | Administrative & support | 2010 |
| Irisk Services Limited | Information & communication | 2015 |
| Iron Bridge Homes Ltd | Real estate | 2023 |
| Isaac Creative Hair Ltd | Other services | 2022 |