| Jeysiva Retail Limited | Wholesale & retail | 2026 |
| JFC Retail Solutions Limited | Construction | 2016 |
| JGS Financial Ltd | Professional & scientific | 2020 |
| JH Decs Limited | Construction | 2020 |
| JH Hires Ltd | Transport & logistics | 2015 |
| JHB Maintenance Limited | Construction | 2025 |
| JHL Consulting Limited | Information & communication | 2010 |
| JHL Contracting Limited | Construction | 2005 |
| JHM Contracts Limited | Construction | 2017 |
| JHM Property Solutions Ltd | Real estate | 2024 |
| Jiad Solutions Ltd | Professional & scientific | 2002 |
| Jinc Projects Ltd | Construction | 2018 |
| JJD Mechanical Services Limited | Administrative & support | 2016 |
| JJL Solutions Limited | Construction | 2003 |
| JJR Ventures Limited | Administrative & support | 2015 |
| JJS Tuition Essex Limited Liability Partnership | | 2013 |
| Jjsg Ltd | Construction | 2020 |
| JK Group London Ltd | Construction | 2019 |
| JK Group Planning Ltd | Information & communication | 2023 |
| JKB Interiors Limited | Construction | 2023 |
| JKS Logistical Limited | Transport & logistics | 2024 |
| JL Collection Limited | Real estate | 2023 |
| JL of Properties Limited | Real estate | 2024 |
| JL Transport (Essex) Ltd | Transport & logistics | 2004 |
| JLA Productions Limited | Information & communication | 2015 |
| JLT54 Properties Limited | Real estate | 2022 |
| JM & P Cook Limited | Agriculture & fishing | 2017 |
| JM Smart Repairs South East Essex Ltd | Wholesale & retail | 2021 |
| JMA Co-Operation Ltd | Real estate | 2020 |
| JMA Drylining Limited | Information & communication | 2015 |
| JMB Capital LLP | | 2018 |
| JMB Consultancy Services Limited | Professional & scientific | 2017 |
| JMG Project Services Limited | Construction | 2025 |
| JMI Flooring Limited | Wholesale & retail | 2002 |
| JMM Contracts Ltd | Construction | 2013 |
| JMP Advisory Ltd | Professional & scientific | 2025 |
| JN Alignment Group Ltd | Information & communication | 2026 |
| JN Interiors Limited | Manufacturing | 2019 |
| JNZ Holdings Ltd | Financial services | 2019 |
| Joanne Tucker Limited | Professional & scientific | 2026 |
| Jodell Construction Services Ltd | Construction | 2019 |
| JOE Loftus Electrical Ltd | Construction | 2025 |
| JOE Public Media Limited | Manufacturing | 2002 |
| Joe's V & a Ltd | Wholesale & retail | 2015 |
| Joelson Logistics & E-Commerce Ltd | Transport & logistics | 2026 |
| John Clarke UK Limited | Administrative & support | 2019 |
| John Clifford (Pharma) Consultancy Services Limited | Information & communication | 2016 |
| John King Associates Limited | Professional & scientific | 2011 |
| John Russell Transport Limited | Transport & logistics | 2007 |
| John Sime & Associates Limited | Professional & scientific | 2006 |
| Johnson Estate Management Ltd | Real estate | 2022 |
| Johnson's Electrical Ltd | Construction | 2025 |
| Johnson's of Leigh Limited | Wholesale & retail | 2002 |
| Johnston Financial Group Limited | Financial services | 2026 |
| Jojo Loves Limited | Professional & scientific | 2018 |
| Joll Limited | Real estate | 2020 |
| Jolly Good Journeys Ltd | Administrative & support | 2011 |
| Jolly Good Tours Limited | Administrative & support | 2025 |
| Jomar Building Services Ltd | Construction | 2019 |
| Jones Home Concepts Ltd | Construction | 2021 |
| Jones Stone Services Ltd | Construction | 2014 |
| Jonsson Interim Limited | Professional & scientific | 2023 |
| Jooles Consultancy Ltd | Professional & scientific | 2026 |
| Joshua Martin Group Limited | Construction | 2025 |
| Joule Developments Limited | Construction | 2014 |
| Joyasha Ltd | Hospitality | 2019 |
| JP Construction 1 Limited | Wholesale & retail | 2018 |
| JP Consulting Solutions Ltd | Professional & scientific | 2021 |
| JP Interiors (Essex) Ltd | Construction | 2020 |
| JP W3 Consulting Ltd | Professional & scientific | 2024 |
| JPG Mortgages Ltd | Financial services | 2023 |
| JPJ Finance Limited | Financial services | 2024 |
| JPL Vehicle Sales Limited | Wholesale & retail | 2015 |
| JPM Group Services Ltd | Construction | 2023 |
| JPR Tuition Services Ltd | Education | 2026 |
| JPS Ministries Ltd | Other services | 2020 |
| JQ Telecom Solutions Ltd | Information & communication | 2022 |
| Jqonline Limited | Wholesale & retail | 2021 |
| JR Prestige Motors Ltd | Wholesale & retail | 2024 |
| JR Property Holdings Limited | Real estate | 2018 |
| Jraphill Consulting Ltd. | Other services | 2024 |
| JRD Heating Ltd | Manufacturing | 2024 |
| JRS Electrical Contractors Limited | Construction | 2019 |
| JSA Group Ltd | Professional & scientific | 2025 |
| JSK HR Solutions Ltd | Administrative & support | 2021 |
| Jsos Holdings Ltd | Financial services | 2023 |
| Jsos Investments Ltd | Real estate | 2023 |
| Jssa Properties Limited | Real estate | 2017 |
| JSW Services Limited | Construction | 2017 |
| JTA Supplies Limited | Wholesale & retail | 2020 |
| JTK Safety Solutions Limited | Construction | 2025 |
| JTM Business Services Ltd | Construction | 2012 |
| Jtmm Consultancy Ltd | Construction | 2020 |
| Jtomm Limited | Professional & scientific | 2019 |
| Jubilee Lettings & Property Sales Limited | Real estate | 2009 |
| Jubilee Place Management Company Limited | Households | 2007 |
| Jubilee Sales and Property Management Limited | Real estate | 2021 |
| Julian Christian (Workshop & Joinery Services) Ltd | Construction | 2020 |
| Juniper Maintenance Ltd | Administrative & support | 2023 |
| Just Another Coffee Shop Limited | Hospitality | 2023 |