| Includingsport Ltd | Arts & recreation | 2005 |
| Independent Passive Fire Inspections Ltd | Public administration | 2021 |
| Indigo Scaffolding Limited | Construction | 2015 |
| INJ Enterprises Limited | Wholesale & retail | 2010 |
| Insightflow Ltd | Information & communication | 2020 |
| Inspire Design Interiors Ltd | Other services | 2006 |
| Instant Drains Limited | Water & waste | 2014 |
| Intelliance Limited | Information & communication | 2018 |
| Intumescent Fire Protection Ltd | Public administration | 2023 |
| Inventive Software Solutions Limited | Real estate | 1989 |
| Ircon Property Group Limited | Real estate | 2024 |
| Iron Edge Ltd | Arts & recreation | 2021 |
| Irvine Management Services Limited | Professional & scientific | 2014 |
| Isurveyor Ltd | Information & communication | 2011 |
| J & R Brothers Ltd | Hospitality | 2015 |
| J J Bensons Electrical Ltd | Energy | 2010 |
| J Lamb Consulting Limited | Professional & scientific | 2025 |
| J P Mitchell Accountants Limited | Professional & scientific | 2017 |
| J P Mitchell Holdings Limited | Financial services | 2022 |
| J P Mitchell Properties Limited | Real estate | 2020 |
| J Reynolds (Builders) Limited | Construction | 2006 |
| J&T Solutions Ltd | Construction | 2014 |
| J.M.Cottis Construction Ltd | Construction | 2020 |
| Jacobs Climacus Ltd | Professional & scientific | 2022 |
| Jacsi Limited | Real estate | 2003 |
| Jahlight Limited | Information & communication | 2025 |
| JAY Saunders Photography Ltd | Professional & scientific | 2020 |
| JB Premises Ltd | Real estate | 2025 |
| JD Roofing Services Ltd | Construction | 2026 |
| Jennerator Limited | Construction | 2020 |
| JF Essex Ltd | Professional & scientific | 2019 |
| JG England Property Services Limited | Real estate | 2020 |
| JGJ Property Investments Ltd | Real estate | 2017 |
| JH Construction Essex Limited | Construction | 2025 |
| JJ Ryan M&E Ltd | Construction | 2023 |
| JJB Payroll Services Ltd | Professional & scientific | 1998 |
| JJT Mechanical Limited | Construction | 2022 |
| Jkml Trading Limited | Financial services | 2016 |
| JLC Markets Limited | Financial services | 2022 |
| JOE Lake Refrigeration Services Limited | Construction | 2001 |
| John JB Ltd | Information & communication | 2017 |
| John Pines Limited | Construction | 2003 |
| John Simmons (Property Management) Limited | Households | 2002 |
| John Watson Properties Limited | Real estate | 2023 |
| Jojaroma Ltd | Financial services | 2020 |
| JP Dining Ltd | Administrative & support | 2016 |
| JRB Skips UK Ltd | Administrative & support | 2020 |
| JS Rental Group Limited | Administrative & support | 2025 |
| JSL Productions Ltd | Construction | 2022 |
| JSS Construction Services Limited | Construction | 2025 |
| JT Flooring Designs Ltd | Professional & scientific | 2026 |
| Judd Luca Ltd | Arts & recreation | 2026 |
| Just Because KG Ltd | Hospitality | 2022 |
| Just Hedging Ltd | Wholesale & retail | 2025 |
| Just Jets Pressure Washing Ltd | Administrative & support | 2025 |
| JWP Moulds Limited | Manufacturing | 2002 |
| K & L Burroughs Limited | Financial services | 2009 |
| K J Evans Electrical Limited | Construction | 1999 |
| K.A. Halfhide Limited | Real estate | 1956 |
| Kaizen Furniture Makers Limited | Manufacturing | 1994 |
| Kaizen Furniture Trustees Ltd | Professional & scientific | 2026 |
| Kamrows Ltd | Wholesale & retail | 2024 |
| Kazi Tavern Ltd | Hospitality | 2026 |
| KBG Holdings Ltd | Financial services | 2024 |
| KBG Property Investment Ltd | Real estate | 2024 |
| KC & Co. Property Group Ltd | Real estate | 2025 |
| Keane Property Group Limited | Real estate | 2016 |
| Keane Property Investment Limited | Real estate | 2021 |
| Keane Property Services Ltd | Administrative & support | 2021 |
| Kelly Designs Limited | Professional & scientific | 2004 |
| Kenmare Bidco Ltd | Financial services | 2024 |
| Kenmare Limited | Manufacturing | 1992 |
| Key Fibre Ltd | Administrative & support | 2022 |
| KG Gym Ltd | Arts & recreation | 2024 |
| Kiloskouriers Ltd | Transport & logistics | 2021 |
| Kingfisher Maritime Consulting Limited | Professional & scientific | 2013 |
| KLH Expansion Limited | Real estate | 2025 |
| Klmm Ltd | Administrative & support | 2022 |
| Kobi and Friends Pet Boutique Ltd | Wholesale & retail | 2024 |
| KPH Plastering & Rendering Ltd | Construction | 2023 |
| Krafft Jewellers Limited | Wholesale & retail | 2003 |
| Krazy Kidz Cafe Limited | Hospitality | 2010 |
| KRH Group Limited | Financial services | 2023 |
| Krystle Recruitment Solutions Ltd | Administrative & support | 2019 |
| Kube Limited | Information & communication | 1997 |
| Kwil Media Limited | Professional & scientific | 2024 |
| L Bleazey Carpentry Limited | Construction | 2015 |
| L D James Contractors Ltd | Administrative & support | 2016 |
| L Smith Electrical Ltd | Construction | 2020 |
| L&R Building Ltd | Construction | 2024 |
| L&R Stone Ltd | Construction | 2021 |
| L3W Scaffolding Ltd | Construction | 2021 |
| Lake Management Limited | Administrative & support | 1990 |
| Landshark Holdings Limited | Professional & scientific | 2023 |
| Lane Gardner Holdings Ltd | Real estate | 2007 |
| Lars Recovery Ltd | Health & social care | 2025 |
| Lavender Grove Cares Ltd. | Health & social care | 2017 |
| Lavender Grove Social Care Agency Ltd | Health & social care | 2021 |
| Lavers Holdings Limited | Financial services | 2025 |
| Lawnhopper (South West Essex) Limited | Other services | 2009 |