| Hudson Druce Capital Limited | Financial services | 2025 |
| Hudson Druce Holdings Limited | Professional & scientific | 2016 |
| Hudson Druce Property Limited | Real estate | 2023 |
| Hull & Company Brentwood Limited | Professional & scientific | 2017 |
| Hull & Company Ilford Limited | Professional & scientific | 2013 |
| Humblecrest Limited | Real estate | 1982 |
| Humphrey, Robertson & Perry Ltd | Construction | 2016 |
| Hunter Fire Services Ltd | Construction | 2026 |
| Huntingdon Capital Limited | Professional & scientific | 2018 |
| Hunts Heating Ltd | Construction | 2026 |
| Hunts of Hutton Ltd | Construction | 2019 |
| Huntswell Ltd | Extraterritorial | 2026 |
| Hurst Executive Search Ltd. | Administrative & support | 2003 |
| Hussain’S Indian Ltd | Hospitality | 2020 |
| Hutchinson Financial Planning Limited | Administrative & support | 2004 |
| Hutton ALL Saints' Church of England Primary Trust | Education | 2011 |
| Hutton Enterprises Ltd | Professional & scientific | 2015 |
| Hutton FC Holdings Limited | Arts & recreation | 2015 |
| Hutton FC Senior Team Company Limited | Arts & recreation | 2024 |
| Hutton Fish Bar Ltd | Hospitality | 2025 |
| Hutton Football Club Trading Company Limited | Arts & recreation | 2018 |
| Hutton Home Improvements Ltd | Construction | 2025 |
| Hutton Masonic Hall,Limited | Other services | 1924 |
| Hutton Plumbing and Heating Solutions Ltd | Administrative & support | 2020 |
| Hutton Surfacing Ltd | Construction | 2023 |
| HV3 Limited | Professional & scientific | 2007 |
| Hvac Limited | Professional & scientific | 1994 |
| Hvac Plant Proving Limited | Construction | 1976 |
| HVB Investments Limited | Real estate | 2025 |
| HW Payroll Limited | Administrative & support | 2008 |
| Hyde & Evans Group Ltd | Construction | 2025 |
| Hyde Plant Services Ltd | Construction | 2017 |
| Hydra Construction Group Ltd | Construction | 2023 |
| Hydra Holdings 2025 Ltd | Financial services | 2025 |
| Hyg-Service Limited | Health & social care | 2022 |
| Hyland Risk Advisory Limited | Professional & scientific | 2016 |
| Hymprove Limited | Information & communication | 2023 |
| Hyperion Property Services Ltd | Extraterritorial | 2021 |
| Hypnosense Limited | Administrative & support | 2007 |
| Hyred Ltd | Administrative & support | 2024 |
| Hyside Motorcycles Ltd | Wholesale & retail | 2013 |
| I & a Assets Limited | Real estate | 2014 |
| I & E Trading Limited | Manufacturing | 2014 |
| I CAN Career Coaching Limited | Professional & scientific | 2026 |
| I GOT Shoes Ltd | Health & social care | 2014 |
| I M a Construction Limited | Real estate | 2019 |
| I-Revolut Consulting Limited | Information & communication | 2021 |
| I65:24 Holdings Ltd | Real estate | 2026 |
| IAM Events Hire Ltd. | Administrative & support | 2013 |
| IAN Humberstone Limited | Real estate | 2001 |
| IAN Hutchings Limited | Other services | 2011 |
| IAN Rowe Associates Ltd | Professional & scientific | 2010 |
| Iangum Luxury Property’S Ltd | Real estate | 2025 |
| Iangum Sports Ltd | Wholesale & retail | 2026 |
| Ibby's Snack Bar Ltd | Hospitality | 2025 |
| Ibiza Booked Ltd | Administrative & support | 2019 |
| Iboga Insight Ltd | Health & social care | 2025 |
| Icab Express Ltd | Transport & logistics | 2023 |
| ICB Consulting Limited | Professional & scientific | 2015 |
| Ice Risk Management Limited | Financial services | 2016 |
| Ichica Hair Limited | Other services | 2023 |
| Ichild Limited | Administrative & support | 2018 |
| Icon Travel Essex Limited | Arts & recreation | 2015 |
| Iconic Brand Licensing Limited | Wholesale & retail | 2017 |
| Iconic Lightbox Limited | Wholesale & retail | 2018 |
| Iconomy Capital House Limited | Real estate | 2024 |
| Iconomy Office Division Limited | Financial services | 2024 |
| Iconomy Quality Court Limited | Real estate | 2025 |
| ID Mind.Health Ltd | Information & communication | 2023 |
| ID Passport Ltd | Information & communication | 2025 |
| ID47 Ltd | Manufacturing | 2024 |
| Ideal Contracts Ltd | Water & waste | 2021 |
| Ideal Motor Group Ltd | Wholesale & retail | 2023 |
| Ideals Wholesale LLP | | 2019 |
| Identify Analytic Data Information Juridic Justice Ltd | Agriculture & fishing | 2025 |
| Identity 3RD Floor Warwick House Limited | Real estate | 2024 |
| IDF Advisory Ltd | Professional & scientific | 2020 |
| Idlemynd Ltd | Information & communication | 2019 |
| Ifindmeta Ltd | Administrative & support | 2022 |
| Ifindtech Ltd | Administrative & support | 2015 |
| Ifysmat Health Care Limited | Health & social care | 2024 |
| Ignis Fire Prevention Ltd | Public administration | 2020 |
| Ignite Purple Social Care Ltd | Health & social care | 2022 |
| III Estates Limited | Other services | 2022 |
| IJL Property Management Limited | Real estate | 2014 |
| IL Payroll Services Ltd | Professional & scientific | 2019 |
| ILI Limited | Information & communication | 2005 |
| Illuminate PR Ltd | Professional & scientific | 2019 |
| Illuminatech Ltd | Wholesale & retail | 2017 |
| Illuvia Limited | Information & communication | 2021 |
| ILO Auto Care Ltd | Wholesale & retail | 2014 |
| Ilya Consulting Limited | Wholesale & retail | 2005 |
| IM Residences Limited | Hospitality | 2025 |
| Image Worx Signs & Graphics Limited | Manufacturing | 2009 |
| Imagine HOW Limited | Professional & scientific | 2024 |
| Immanuel Church Brentwood | Other services | 2013 |
| Immigrationely.Com Ltd | Professional & scientific | 2025 |
| Impact Plus Media Ltd | Information & communication | 2026 |
| Impactalpha Ltd | Professional & scientific | 2021 |
| Impax Recruitment Ltd | Administrative & support | 2021 |