| Homevolution Ltd | Construction | 2020 |
| Hopwood Finance Ltd | Financial services | 2014 |
| Hornchurch Electrical Contractors Ltd | Construction | 2022 |
| Hot & Cold Installations Ltd | Construction | 2000 |
| Hot & Cold Installations Plumbing and Heating Ltd | Construction | 2025 |
| House 71 Ltd | Real estate | 2012 |
| House of Anthelya Limited | Wholesale & retail | 2025 |
| House of Kais Ltd | Administrative & support | 2025 |
| Hoxton Services LLP | | 2014 |
| HPS Tax Limited | Professional & scientific | 2011 |
| Huckfield Property Ltd | Construction | 2019 |
| Huggos Ltd | Manufacturing | 2023 |
| Hume Cleaning Services Ltd | Administrative & support | 2023 |
| HUN Hair Ltd | Other services | 2019 |
| Hunter & Co Ltd | Professional & scientific | 2011 |
| Hunter Property Projects Ltd | Construction | 2019 |
| Hunter Real Estate Ltd | Real estate | 2025 |
| Hunter UK Properties Ltd | Construction | 2013 |
| Hutton Properties Limited | Households | 2005 |
| I B Electrical Contractors Ltd | Wholesale & retail | 2020 |
| I-Fix Scaffolding Limited | Construction | 2019 |
| IAN Socaciu Limited | Construction | 2019 |
| IB Property Development Ltd | Construction | 2020 |
| IC Contracts Ltd | Construction | 2022 |
| ICB Solutions Limited | Real estate | 2024 |
| Icefox Developments Limited | Construction | 2008 |
| Icon Residential Limited | Real estate | 2008 |
| Ifly Electric UK Ltd | Manufacturing | 2019 |
| Illustration & Design Limited | Professional & scientific | 2004 |
| Image Global Ltd. | Wholesale & retail | 2019 |
| Image Healthcare Limited | Health & social care | 2025 |
| Impact Solutions Ltd | Professional & scientific | 2025 |
| In-Woodvision Limited | Other services | 2019 |
| Industrial Diesel Diagnostic & Repair Ltd | Wholesale & retail | 2023 |
| Ineland Ltd | Administrative & support | 2016 |
| Infinite Skin Clinic Ltd | Other services | 2025 |
| Infinity Ventures 360 Ltd | Information & communication | 2016 |
| Infitness Gym Ltd | Arts & recreation | 2013 |
| Influence Audience Limited | Extraterritorial | 2016 |
| Ingen Consulting Limited | Information & communication | 2007 |
| INI Legal Services Ltd | Professional & scientific | 2025 |
| Inketch Ltd | Wholesale & retail | 2021 |
| Innovation Medicare Ltd | Health & social care | 2019 |
| Innovation Properties & Homes Ltd | Real estate | 2025 |
| Insite FM Ltd | Administrative & support | 2019 |
| Inspired Cleaning Ltd | Administrative & support | 2013 |
| Instant Baits Ltd | Manufacturing | 2025 |
| Instillness Ltd | Professional & scientific | 2022 |
| Integrity Data Solutions Ltd | Professional & scientific | 2017 |
| Intelligent Contract Services Ltd | Professional & scientific | 2021 |
| Intent to Success Ltd | Financial services | 2021 |
| Inter-Maritime Forwarding Co. (U.K.) Limited | Extraterritorial | 1988 |
| Interec Properties Ltd | Real estate | 2022 |
| International Chemical Products Limited | Manufacturing | 2012 |
| International Heart Clinic Ltd | Health & social care | 2020 |
| Into the Cloud Ltd | Information & communication | 2024 |
| Intrepid IT Ltd | Information & communication | 1998 |
| Invertex IT Limited | Information & communication | 2026 |
| Ioena Cleaning Service Ltd | Administrative & support | 2026 |
| IOM Construction Ltd | Construction | 2020 |
| IR Consultants Ltd | Professional & scientific | 2020 |
| IRI Property Ltd | Real estate | 2022 |
| ISO Corecert Limited | Professional & scientific | 2025 |
| Isotope Consulting Ltd | Professional & scientific | 2009 |
| IV Rail Ltd | Construction | 2010 |
| IYKYK8TS Ltd | Wholesale & retail | 2024 |
| J & a Proper T Ltd | Real estate | 2020 |
| J & R Franchise Limited | Hospitality | 2024 |
| J and H Accountants Ltd | Professional & scientific | 2023 |
| J D Rafferty Ltd | Manufacturing | 2019 |
| J Ebsworth Build Ltd | Administrative & support | 2005 |
| J Francomb (Holdings) Ltd | Health & social care | 2024 |
| J K Jointing (Essex) Ltd | Manufacturing | 2015 |
| J P Reilly Scaffolding Ltd | Construction | 2025 |
| J W Emery Limited | Professional & scientific | 2015 |
| J W M Cleaning Services Ltd | Administrative & support | 2008 |
| J.J. Services Developments Ltd | Hospitality | 2009 |
| J.L.M. (Essex) Ltd | Construction | 2011 |
| J.P.B. Harris & Co. Limited | Professional & scientific | 1993 |
| J9 Roofing Ltd | Construction | 2022 |
| Jack Bunney Limited | Wholesale & retail | 1958 |
| Jack of ALL Trades Essex Ltd | Construction | 2023 |
| Jack's FAT Jackets Ltd | Wholesale & retail | 2025 |
| Jack's Patch Limited | Agriculture & fishing | 2020 |
| Jackson and Johnson Limited | Manufacturing | 2015 |
| Jackson Lettings Limited | Real estate | 2017 |
| Jacksons Facilities Ltd | Construction | 2018 |
| Jade Green Productions Limited | Administrative & support | 2020 |
| Jaek Highway Services Limited | Construction | 2013 |
| JAG Property Management Ltd | Real estate | 2017 |
| Jaida Real Estate Limited | Real estate | 2023 |
| Jambass Holdings Limited | Financial services | 2025 |
| Jambass Ltd | Information & communication | 2024 |
| James Anthony Gallery Ltd | Wholesale & retail | 2022 |
| James Read Opticians Ltd | Wholesale & retail | 2002 |
| Jaml Properties Ltd | Construction | 2022 |
| Jaranza (UK) Ltd | Real estate | 2017 |
| Jarrett Group (Essex) Ltd | Financial services | 2022 |
| Jarrett Holdings Limited | Real estate | 2017 |
| Jarrett Services LLP | | 2021 |