| Huggs for Homes Limited | Real estate | 2017 |
| Humphreys Financial Management Ltd. | Professional & scientific | 1994 |
| Huseyin K Properties Ltd | Real estate | 2019 |
| HV Oakley Meadows Services Limited | Construction | 2024 |
| Ideate Ltd | Professional & scientific | 2003 |
| Indago Recruitment Ltd | Transport & logistics | 2011 |
| Independent Survey Services Ltd | Transport & logistics | 2016 |
| Infinity Products Limited | Professional & scientific | 2018 |
| Inland Waterways Specialists Ltd | Construction | 2021 |
| Inn Stock Ltd | Administrative & support | 2010 |
| INNOV8 Architecture Ltd | Professional & scientific | 2026 |
| Innovate Electrical Ltd | Construction | 2014 |
| Ipex Telecom Limited | Information & communication | 2015 |
| It's Different Limited | Wholesale & retail | 2023 |
| J & W Events Limited | Arts & recreation | 2025 |
| J Law Carpentry Limited | Construction | 2011 |
| J Lungley Site Management Ltd | Construction | 2016 |
| J&M Homecare Ltd | Health & social care | 2020 |
| Jacks Jetwashing Ltd | Administrative & support | 2024 |
| Jackson Codd Limited | Construction | 2021 |
| Jacquelines of Colchester Tea Rooms Ltd | Hospitality | 2018 |
| Jagasaalu UK Limited | Wholesale & retail | 2018 |
| Jaguar Love Ltd | Construction | 2019 |
| Jake Piercy Ltd | Construction | 2017 |
| James French Renovations Limited | Construction | 2025 |
| JC White Group Ltd | Professional & scientific | 2018 |
| Jcmc Services Ltd | Transport & logistics | 2017 |
| JH Traffic Limited | Construction | 2023 |
| Jj’S Cabs Ltd | Transport & logistics | 2023 |
| JK Sliding Door Consultancy Ltd | Professional & scientific | 2018 |
| Jkonda Services Limited | Professional & scientific | 2020 |
| JND Engineering Ltd | Manufacturing | 2026 |
| JOE Chippington Limited | Construction | 2018 |
| Johnny James Limited | Construction | 2024 |
| Journawell Ltd | Administrative & support | 2025 |
| JPS Industrial Roofing Ltd | Construction | 2024 |
| JRK Collectables Ltd | Wholesale & retail | 2025 |
| JT Wheel Refurbishment & Powder Coating Limited | Wholesale & retail | 2024 |
| Just Drainage Ltd | Water & waste | 2026 |
| JWH Fabrications Ltd | Manufacturing | 2018 |
| JWP Crysell Ltd | Wholesale & retail | 2023 |
| K & K Surveying Ltd | Administrative & support | 2022 |
| K Howe Installations Ltd | Construction | 2023 |
| Kanga Couriers Limited | Transport & logistics | 2008 |
| Kangaroo Local UK Ltd | Wholesale & retail | 2024 |
| Kayhan's Property Ltd | Real estate | 2025 |
| KB Parrish Limited | Transport & logistics | 2024 |
| KBL Painting & Decorating Limited | Construction | 2025 |
| KBM Property Ltd | Households | 2024 |
| KCN Land Limited | Construction | 2018 |
| Kellett Grove UK Limited | Professional & scientific | 2022 |
| KEN Stapleton and SON Ltd | Construction | 2014 |
| Kentrox Limited | Administrative & support | 2025 |
| Kerfuffle Marketing Ltd | Information & communication | 2025 |
| Key Associates Limited | Professional & scientific | 1993 |
| Kidaroo Ltd | Wholesale & retail | 2025 |
| Kidd's Composites Ltd | Manufacturing | 2019 |
| Kinetic Renewables Ltd | Energy | 2022 |
| Kingsway Hair & Beauty Ltd | Other services | 2016 |
| KIP Khess Finance UK Ltd | Education | 2026 |
| Kirk Innovations Limited | Information & communication | 2006 |
| Kotiy Ltd | Manufacturing | 2025 |
| Lagares.Sisters Ltd | Professional & scientific | 2025 |
| Lanark Interiors Ltd | Construction | 2019 |
| Landguard Engineering Limited | Manufacturing | 2013 |
| Landguard Holdings Limited | Financial services | 2004 |
| Laruka Ltd | Real estate | 2025 |
| Last Chance Saloon Ltd | Hospitality | 2023 |
| Leonard & Davies Developments Limited | Real estate | 2005 |
| Liath Mactire Foglama Ltd. | Arts & recreation | 2013 |
| Ligart Ltd | Transport & logistics | 2024 |
| Little Big Tech Harwich Ltd | Information & communication | 2023 |
| Little Oakley Football Club Limited | Arts & recreation | 2021 |
| LKS Elite Car Keys Ltd | Other services | 2025 |
| Llatkins Property Solutions Ltd | Real estate | 2019 |
| LSG Heating Services Ltd | Construction | 2024 |
| Lucali Limited | Professional & scientific | 2013 |
| LUCKY8 DK Ltd | Transport & logistics | 2022 |
| Luminarium AI Ltd | Information & communication | 2025 |
| Luminous Leaf Skincare Ltd | Extraterritorial | 2023 |
| M a Steel Fabrication Ltd | Manufacturing | 2024 |
| M Baxter Consultants Ltd | Professional & scientific | 2023 |
| M R Payne Accountancy & Taxation Services Ltd | Professional & scientific | 2002 |
| M-Bailey Transport Limited | Transport & logistics | 2018 |
| M-Ship Limited | Professional & scientific | 2005 |
| Maldon Estates Limited | Real estate | 1999 |
| Manchester Crown Packaging Ltd | Wholesale & retail | 2026 |
| Mann Group Limited | Professional & scientific | 1993 |
| Mann Lines Limited | Transport & logistics | 2001 |
| Mann Lines Multimodal Limited | Transport & logistics | 2001 |
| Marine Construction & Lifting Consultants Ltd | Construction | 2023 |
| Mark Anthony Bespoke Limited | Manufacturing | 2012 |
| Mark Solution Ltd | Wholesale & retail | 2025 |
| Marshman Electrical Limited | Construction | 2024 |
| Mayflower Financial Planning Limited | Financial services | 2019 |
| Mayflower Medical Centre Limited | Health & social care | 2005 |
| Mbeminicabs Ltd | Transport & logistics | 2025 |
| MCL Accountants NEE Limited | Professional & scientific | 2019 |
| MCL Payroll Services Limited | Administrative & support | 2021 |
| Mdand SON Property Limited | Real estate | 2026 |