| HS Oxford Lettings Limited | Real estate | 2022 |
| HS Property Holdings Ltd | Real estate | 2021 |
| HS Wheatley Holdings (NO 1) Limited | Real estate | 2024 |
| HS Wheatley Holdings (NO 2) Limited | Real estate | 2024 |
| HSA Cars Ltd | Wholesale & retail | 2024 |
| HSH Property Group Ltd | Real estate | 2025 |
| HSM Prospera Ltd | Financial services | 2025 |
| HTA Finance Limited | Administrative & support | 2019 |
| Hublush Co Ltd | Hospitality | 2024 |
| Hubsolutions Limited | Information & communication | 1997 |
| Hulmow Properties Limited | Construction | 1962 |
| Hundred Showroom Limited | Professional & scientific | 2019 |
| Hung Nguyen Nail Ltd | Other services | 2023 |
| Hunter Tool Systems (Europe) Limited | Wholesale & retail | 2020 |
| Hurstbourne Priors Freeholders Limited | Households | 2002 |
| Hush Babies Maternity Services by Bernie Ltd | Health & social care | 2025 |
| HUT11 Ltd | Information & communication | 2025 |
| HW Financial Consulting Limited | Professional & scientific | 2018 |
| Hyatt Services Limited | Construction | 1990 |
| Hyde & Rowe Crystal Palace Ltd | Households | 2025 |
| Hyde and Rowe Limited | Real estate | 2008 |
| Hyde Asset Management Limited | Real estate | 2017 |
| Hygieia Care Limited | Health & social care | 2019 |
| Hylton Construction Ltd | Construction | 2025 |
| Hypermind Limited | Professional & scientific | 2014 |
| I AM Agenci Ltd | Information & communication | 2024 |
| I SEE Media Ltd | Professional & scientific | 2018 |
| Ianasur Limited | Real estate | 2016 |
| Ibar Ltd | Hospitality | 1999 |
| Ibis Works Ltd | Professional & scientific | 2025 |
| ICM LDN Ltd | Information & communication | 2023 |
| ICP (UK) Limited | Other services | 2003 |
| ID Prestige Autos Limited | Wholesale & retail | 2023 |
| IDB Consulting Limited | Information & communication | 2014 |
| IDE Solution Ltd | Administrative & support | 2018 |
| Idlebeck Property Ltd | Real estate | 2019 |
| Idoneus Administration Services Limited | Administrative & support | 2017 |
| Ifeco Investment Limited | Wholesale & retail | 2018 |
| Ifybelen Ltd | Other services | 2013 |
| IGT DRY Cleaners Ltd | Other services | 2026 |
| Iguarias DA Terra Limited | Wholesale & retail | 2025 |
| IKE Shieldguard Ltd | Professional & scientific | 2025 |
| ILA Marketing Services Limited | Professional & scientific | 2016 |
| ILG Communications Ltd | Professional & scientific | 2023 |
| Ilke Industrial Limited | Manufacturing | 2019 |
| Immaculate Building and Plumbing Ltd | Construction | 2014 |
| Impact Alive Ministries | Other services | 2017 |
| Imperial Land & Estates Limited | Real estate | 2022 |
| Imperial Ministries Limited | Hospitality | 2018 |
| Imperial Mousse Limited | Real estate | 2023 |
| Imperial Way Services Limited | Real estate | 2022 |
| Impinch (SPV) Limited | Real estate | 2023 |
| Impinch Limited | Real estate | 1980 |
| Impressive Tech Managed Services Ltd | Information & communication | 2023 |
| Improved Cognition Ltd | Health & social care | 2025 |
| Imsa Investments Ltd | Real estate | 2022 |
| Imsha Pharma Solutions Ltd | Professional & scientific | 2026 |
| IMT International Dialyse Ltd | Water & waste | 2013 |
| IN Praxi Education Group Ltd. | Professional & scientific | 2019 |
| Inchaud Holdings Ltd | Arts & recreation | 2013 |
| Inclusive Online Activities Limited | Education | 2020 |
| Incos Properties Ltd | Real estate | 2024 |
| Incredible Europe Ltd | Administrative & support | 2024 |
| Indigo Court Limited | Real estate | 2014 |
| Indigo Systems Limited | Construction | 2005 |
| Inex Consult Ltd | Construction | 2025 |
| Inferno Knight Distribution Ltd | Wholesale & retail | 2026 |
| Infernö Class Recörding Limited | Information & communication | 2024 |
| Infinet Point Limited | Information & communication | 2002 |
| Infinite Group Solutions Ltd | Manufacturing | 2023 |
| Infinity Transformation Solutions Ltd | Professional & scientific | 2016 |
| Informatics LAB Ltd | Information & communication | 2025 |
| Ingaran & Brother Ltd | Wholesale & retail | 2022 |
| Inglewood Estate (Freehold) Limited | Households | 2000 |
| Inglewood Estate Management Company Limited | Households | 1975 |
| Ingram Home Improvements Ltd | Construction | 2020 |
| Inimitable Engineering Services - Civils Limited | Construction | 2025 |
| INK by CC Ltd | Arts & recreation | 2026 |
| Inn on the Park Limited | Hospitality | 2025 |
| Innowave Ltd | Administrative & support | 2017 |
| Insight WI Ltd | Real estate | 2019 |
| Insightedge Ltd | Information & communication | 2025 |
| Instant Heating & Plumbing Solutions Ltd | Construction | 2017 |
| Instantmedicals Ltd | Health & social care | 2018 |
| Intellicreate.Ai Ltd | Information & communication | 2025 |
| Intelligent Investments Limited | Real estate | 2007 |
| Inter Force Builders Ltd | Construction | 2019 |
| International Quality Consultancy Ltd | Wholesale & retail | 2021 |
| Intrascape Ltd | Information & communication | 2020 |
| Inveniam Enterprises Ltd | Wholesale & retail | 2011 |
| Invent the Compass Limited | Education | 2023 |
| Invicta International Investments Limited | Financial services | 2023 |
| Invorbis Technologies Ltd | Information & communication | 2026 |
| Iqtelligent Group Ltd | Professional & scientific | 2009 |
| Irene Surrey Limited | Real estate | 2014 |
| Irongate Risk Management Ltd | Administrative & support | 2024 |
| ISA Cleaning&Mantainance Ltd | Construction | 2025 |
| ISA Property Management Ltd | Real estate | 2023 |
| Isearch Global Limited | Information & communication | 2012 |
| Ishanvi Ltd | Information & communication | 2013 |