| Invictus Global Ltd | Professional & scientific | 2018 |
| Invictus Solutions Limited | Information & communication | 2009 |
| IPS Digital Studio Ltd | Information & communication | 2011 |
| Iris Close Management Company Limited | Households | 2017 |
| Irmak INT Ltd | Hospitality | 2025 |
| Ironbridge (H.V.E) Limited | Construction | 2004 |
| Ironwood Contractors Ltd | Construction | 2001 |
| Isaac Construction Ltd | Construction | 2019 |
| Iskus Health UK Ltd | Manufacturing | 2014 |
| Ivan Goodman Transport (UK) Limited | Transport & logistics | 2013 |
| Ivkovic Jewelry Ltd | Manufacturing | 2025 |
| J a Consultants Limited | Professional & scientific | 2009 |
| J and O Group Limited | Financial services | 2018 |
| J Barker Ltd | Construction | 2011 |
| J Chill & SON Ltd | Transport & logistics | 2026 |
| J Cobley Transport Ltd | Transport & logistics | 2021 |
| J J Davison & Sons Limited | Agriculture & fishing | 2010 |
| J J Taylor Ltd | Hospitality | 2016 |
| J M Services (Burntwood) Ltd | Manufacturing | 2011 |
| J Orme & SON (Builders) Limited | Construction | 2003 |
| J Pole Pipework Services Ltd | Manufacturing | 2025 |
| J Reid Electrical Services Limited | Construction | 2022 |
| J S Bloor (Tewkesbury) Limited | Construction | 2000 |
| J S Bloor (Wilmslow) Limited | Construction | 2000 |
| J Wilkins Properties Ltd | Real estate | 2025 |
| J&J Sports Ltd | Education | 2023 |
| J.A. Davis Contractors Limited | Construction | 1962 |
| J.D Stainless Ltd | Construction | 2012 |
| J.H.R. Race Engineering Limited | Manufacturing | 2003 |
| J.I.H. Pods Limited | Administrative & support | 2018 |
| J.J. Alexsean Limited | Health & social care | 2015 |
| J.Pritchard Mortgage Solutions Ltd | Financial services | 2022 |
| J.Pritchard Properties Limited | Real estate | 2024 |
| J.S. Bloor (Investments) Limited | Professional & scientific | 1982 |
| J.S. Bloor (Measham) Limited | Construction | 1952 |
| J.S. Bloor (Milton Keynes) Limited | Construction | 2002 |
| J.S. Bloor (Newbury) Limited | Professional & scientific | 1988 |
| J.S. Bloor Commercial Properties Limited | Professional & scientific | 1972 |
| J.S.Bloor (Northampton) Limited | Construction | 1987 |
| J.S.Bloor (Services) Limited | Construction | 1987 |
| J.S.Bloor (Sudbury) Limited | Construction | 1987 |
| J.S.Bloor (Swindon) Limited | Construction | 1988 |
| J.S.Bloor (Tamworth) Limited | Construction | 1987 |
| J.S.Bloor Limited | Professional & scientific | 1969 |
| JA Davis Developments Limited | Construction | 2026 |
| Jack Jones Electrical Limited | Construction | 2019 |
| Jade Holdings (Properties) Limited | Real estate | 1988 |
| JAJ Holdings Limited | Construction | 2009 |
| Jake Dixon Racing Ltd | Arts & recreation | 2016 |
| Jakub 82 Ltd | Transport & logistics | 2014 |
| James COX Construction Ltd | Construction | 2020 |
| James Hooper Limited | Wholesale & retail | 2007 |
| James's Place (Aldridge) Management Company Limited | Households | 2025 |
| Janet Goode Consulting Ltd | Professional & scientific | 2023 |
| Japonica House Property Limited | Real estate | 2026 |
| Jaydee Homes Limited | Real estate | 1962 |
| JB Logistic Solutions Ltd | Transport & logistics | 2019 |
| JB Services (1992) Ltd | Construction | 2021 |
| JCG M&E Solutions Limited | Construction | 2016 |
| JCH Transport Ltd | Transport & logistics | 2018 |
| Jcrg Ltd | Manufacturing | 2025 |
| JD Firesafe Ltd | Financial services | 2026 |
| JDB Technical Limited | Extraterritorial | 2009 |
| JDH Surveying Ltd | Professional & scientific | 2025 |
| Jega Solutions Ltd | Information & communication | 2014 |
| JEM Psychology Ltd | Education | 2021 |
| Jennings Entertainment and Catering Limited | Hospitality | 2016 |
| JES Interior Solutions Ltd | Construction | 2025 |
| Jessica Ruth Academy Limited | Education | 2024 |
| Jessica Ruth Spmu Ltd | Other services | 2022 |
| JET Wash Aviation Ltd | Administrative & support | 2025 |
| JF Installations Ltd | Wholesale & retail | 2021 |
| JF Weathertech Roofing Ltd | Construction | 2021 |
| JFA Carpentry Limited | Construction | 2016 |
| JHC Construction and Project Management Ltd | Administrative & support | 2025 |
| JHE Developments Ltd | Construction | 2011 |
| Jijjy Music Ltd | Arts & recreation | 2025 |
| Jilly Clarks Shoes Limited | Real estate | 2009 |
| JIM Cummins Transport Limited | Transport & logistics | 2025 |
| JKM Quality Services Ltd | Construction | 2018 |
| JLB Maritime Services Limited | Administrative & support | 2013 |
| JLG Consultancy Ltd | Health & social care | 2021 |
| JLH GAS Services Ltd | Construction | 2018 |
| JLR 4X4 Limited | Wholesale & retail | 2020 |
| JMC Roof Depot Ltd | Construction | 2020 |
| JMD Maintenance Ltd | Construction | 2015 |
| Jmsfitness HQ Ltd | Other services | 2021 |
| JNM Builders Limited | Construction | 2024 |
| Joanne Lockley Limited | Professional & scientific | 2011 |
| John Mason Limited | Agriculture & fishing | 2002 |
| John Wagstaff Limited | Construction | 2003 |
| Johnboy Scrap and Recovery Ltd | Water & waste | 2025 |
| Johnny Edwards Kerb-Laying Ltd | Construction | 2017 |
| Johnson & Co Properties Limited | Professional & scientific | 2020 |
| Jojo’S PUB Company Limited | Hospitality | 2026 |
| Joseph Arthur Homes Limited | Construction | 2022 |
| JQ Sports Massage Ltd | Health & social care | 2020 |
| Jrasales Ltd | Wholesale & retail | 2026 |
| Jrfg Property Ltd | Real estate | 2025 |
| Jrobbocoaching Limited | Health & social care | 2025 |