| Jaye Jaye Property Ltd | Other services | 2020 |
| Jayjaym Limited | Professional & scientific | 2021 |
| Jayray Financial Services Limited | Professional & scientific | 2018 |
| Jayray Specialist Holdings Ltd | Financial services | 2022 |
| JAZ Harris Limited | Professional & scientific | 2023 |
| Jazmine Sport & Thai Massage Ltd | Other services | 2019 |
| JB Electrical Contracts Ltd | Construction | 2020 |
| Jbbn Construction Ltd | Professional & scientific | 2025 |
| JBG Properties Limited | Real estate | 2024 |
| JBL Services and Maintenance Limited | Construction | 2026 |
| JBS Ellis Limited | Professional & scientific | 2026 |
| JC Autocare Ltd | Wholesale & retail | 2022 |
| JCL Trading Essex Limited | Water & waste | 2021 |
| JCM Consulting Group Ltd | Professional & scientific | 2023 |
| JCS Roofing Ltd | Construction | 2022 |
| JD Ground Work Enterprises Limited | Construction | 2022 |
| JD Hire Limited | Administrative & support | 2013 |
| JD Trading Essex Limited | Other services | 2015 |
| JDM Electrical Services Ltd | Construction | 2023 |
| JDP (Ramsgate) Limited | Construction | 2021 |
| JDP (South) Limited | Construction | 2020 |
| JDP (South) Properties Limited | Real estate | 2024 |
| JDP Construction Ltd | Construction | 2017 |
| JDP Homes Ltd | Real estate | 2025 |
| JDP Logistics Services Ltd | Administrative & support | 2024 |
| JDP Professional Services Limited | Real estate | 2019 |
| JDP Storage Limited | Real estate | 2025 |
| JE AAA Ltd | Construction | 2017 |
| JE Fire Projects Ltd | Professional & scientific | 2009 |
| JED Payments Limited | Financial services | 2019 |
| Jeeten IT Solutions Limited | Information & communication | 2022 |
| Jeevan Housing Ltd | Real estate | 2021 |
| Jeff Gross Engineering Limited | Professional & scientific | 2016 |
| Jeffony Home Services Ltd | Real estate | 2023 |
| Jefford & Co. Limited | Wholesale & retail | 2000 |
| JEK Transport Ltd | Transport & logistics | 2026 |
| JEM Motor Group Ltd | Wholesale & retail | 2026 |
| Jensen Kobain Ltd | Professional & scientific | 2013 |
| Jess Holbrook Creative Ltd | Arts & recreation | 2021 |
| JET IT Clean Carpet Specialist Ltd | Administrative & support | 2026 |
| JET IT Clean Ltd | Administrative & support | 2025 |
| Jeth Denahy Cleaning Services Limited | Administrative & support | 2018 |
| Jewellery Finder & Co Ltd | Wholesale & retail | 2018 |
| JFC AML Limited | Administrative & support | 2024 |
| JFL Computing Limited | Information & communication | 1998 |
| Jflb Ltd | Professional & scientific | 2015 |
| JG Timber Ltd | Wholesale & retail | 2022 |
| Jgco Ltd | Real estate | 2018 |
| Jgdh Ltd | Real estate | 2023 |
| Jglc Property Ltd | Real estate | 2022 |
| JGR Electrical Installations Ltd | Construction | 2018 |
| Jiayi Food Limited | Hospitality | 2022 |
| Jibash Limited | Information & communication | 2017 |
| JIJ60 Advisory Ltd | Professional & scientific | 2026 |
| JIM & MO Holdings Limited | Public administration | 2022 |
| JIM 2016 Ltd | Transport & logistics | 2016 |
| Jimmy Morris Holdings Ltd | Financial services | 2025 |
| Jino Property Limited | Real estate | 2018 |
| Jintec Ltd | Information & communication | 2023 |
| JIOEB5 Healthcare Services Ltd | Administrative & support | 2015 |
| JJ Computer Systems Limited | Information & communication | 2020 |
| JJ Logistics 1 Ltd | Construction | 2016 |
| Jj's Essex Limited | Hospitality | 2021 |
| JJE Marlow Property Ltd | Real estate | 2024 |
| JJL Build Ltd | Construction | 2019 |
| JJS Design Limited | Information & communication | 2007 |
| JJS Logistics Limited | Construction | 2014 |
| JJT Plumbing & Heating Limited | Construction | 2018 |
| JK Professional Services Limited | Information & communication | 2016 |
| JK Stewart Electrical Ltd | Construction | 2026 |
| JKB Property Maintenance Limited | Construction | 2025 |
| JLC Dental LAB Limited | Health & social care | 2007 |
| Jlst Properties Ltd | Real estate | 2021 |
| JM Events & Entertainment Limited | Arts & recreation | 2026 |
| JM Wood Recycling Limited | Water & waste | 2025 |
| Jm-Creative Construction Limited | Construction | 2016 |
| JMC Fire Ltd | Public administration | 2018 |
| JMK Consultinguk Limited | Health & social care | 2022 |
| JMK Promotions Limited | Other services | 2015 |
| JML Heating Ltd | Construction | 2025 |
| JML Lettings Ltd | Real estate | 2025 |
| Jmrs Properties Limited | Real estate | 2014 |
| Jmto Ltd | Financial services | 2011 |
| Jo's Party Music Publishing Limited | Information & communication | 2018 |
| Joanne Ponder Ltd | Other services | 2026 |
| JOB Links Recruitment Limited | Administrative & support | 2023 |
| Jobbler UK Ltd | Information & communication | 2024 |
| Jobgenie Technology Ltd | Administrative & support | 2025 |
| JOC Property Solutions Limited | Real estate | 2023 |
| Joca Engineering Ltd | Construction | 2022 |
| Joceo Limited | Information & communication | 2005 |
| JOE Peat Strength and Conditioning Limited | Health & social care | 2014 |
| Joe's Trading Ltd | Construction | 2021 |
| Johal & Company UK Limited | Professional & scientific | 1999 |
| John Arnold Commercials Limited | Wholesale & retail | 1986 |
| John Arnold Commercials Northampton Limited | Wholesale & retail | 2019 |
| John Clark & Sons Butchers Limited | Wholesale & retail | 2011 |
| John Holland Transport Solutions Ltd | Transport & logistics | 2020 |
| John L David Marine Consultant Limited | Administrative & support | 2004 |
| John Peck Associates Ltd | Professional & scientific | 2017 |