| IN2FLOORING (Yorkshire) Ltd | Wholesale & retail | 2020 |
| Inline Mechanical Building Services Ltd | Construction | 2013 |
| J & S England Ltd | Arts & recreation | 2023 |
| J B Pallets Ltd | Wholesale & retail | 2016 |
| J C Metcalfe Building Contractors Ltd | Construction | 2016 |
| J. & a. Batty Bros. Limited | Construction | 1976 |
| Jackson Advanced Services Ltd | Financial services | 2024 |
| Jackson Swiss Partners Commercial Finance Brokers Limited | Financial services | 2026 |
| Jackson Swiss Partners Foreign Exchange Limited | Financial services | 2017 |
| JAD Property Limited | Real estate | 2000 |
| JAH Cleaning Solutions Ltd | Administrative & support | 2023 |
| JAH Stump Grinding Ltd | Agriculture & fishing | 2025 |
| James Kelly Properties Ltd | Real estate | 2021 |
| Jaquard Ltd | Real estate | 2017 |
| Jblukic Ltd | Administrative & support | 2023 |
| JC Creative Services Ltd | Professional & scientific | 2026 |
| JC Developments (Yorkshire) Ltd | Construction | 2024 |
| JC Property Investments (Yorkshire) Ltd | Real estate | 2023 |
| JEM Properties (Manchester) Ltd | Real estate | 2025 |
| JJ Builders (Yorkshire) Ltd | Construction | 2024 |
| JM Properties (Yorkshire) Ltd | Real estate | 2017 |
| John Ayrey Die-Casts Limited | Wholesale & retail | 1996 |
| Jool Fabrications Limited | Manufacturing | 2017 |
| Jool Holdings Limited | Real estate | 2024 |
| JPC (Yorkshire) Limited | Construction | 2007 |
| JPE Property Limited | Hospitality | 2018 |
| JR Rhodes Ltd | Real estate | 2024 |
| Kate Gold Ltd | Wholesale & retail | 2025 |
| KBP Sales & Consultancy Ltd | Professional & scientific | 2024 |
| KCD Build Ltd | Construction | 2021 |
| Key Mark Locksmiths Limited | Manufacturing | 2008 |
| Keystone Education Ltd | Education | 2013 |
| Kids Financial Intelligence's Impact Limited | Education | 2017 |
| Kinevo Coaching Ltd | Information & communication | 2026 |
| Kingfisher Restorations Ltd | Real estate | 2016 |
| Kingslay Carpets Ltd | Construction | 2024 |
| Klaes UK Limited | Information & communication | 2006 |
| Koda Engineering Ltd | Professional & scientific | 2024 |
| Kron Consultancy Limited | Professional & scientific | 2019 |
| Kwoczko Property Ltd | Real estate | 2025 |
| Kynes Group Holdings Limited | Professional & scientific | 2005 |
| L a Horne Joinery Limited | Construction | 2007 |
| L Cole Holdings Ltd | Financial services | 2024 |
| L D Sunyata Property Ltd | Construction | 2023 |
| L J Robson (Contracts) Limited | Construction | 2007 |
| L T ASH Construction Ltd | Construction | 2024 |
| L W Graphics Limited | Information & communication | 2006 |
| Lacu Farms Limited | Agriculture & fishing | 2025 |
| Laura Bond Lettings Limited | Real estate | 2023 |
| Laxton EOT Limited | Administrative & support | 2024 |
| Leeds Courier Services Limited | Transport & logistics | 2017 |
| Levell Property Developments Ltd | Real estate | 2022 |
| Libera Tech Group Ltd | Information & communication | 2022 |
| Lightfoot Properties Ltd | Real estate | 2021 |
| LKR Property Management Ltd | Real estate | 2025 |
| Lloyd Leisure Services Limited | Hospitality | 2023 |
| Lokala Ligor Ltd | Arts & recreation | 2025 |
| Long Summer Holdings Ltd | Real estate | 2025 |
| Lower Springhead Construction Ltd | Construction | 2021 |
| LPM Construction Ltd | Construction | 2014 |
| LPM Property Ltd | Real estate | 2019 |
| Luminus Holdings Ltd | Other services | 2020 |
| M & B Properties (Yorkshire) Ltd | Real estate | 2019 |
| M & D Lefley Limited | Real estate | 2003 |
| M S Browne Limited | Hospitality | 2021 |
| Mamma MIA Limited | Hospitality | 2014 |
| Mamma Napoli Limited | Hospitality | 2014 |
| Manor Coating Systems Limited | Manufacturing | 1938 |
| Maple Red Light Haulage and Express Couriers Ltd | Transport & logistics | 2009 |
| Marcus Nelson Consulting Ltd | Manufacturing | 2015 |
| Mark Izzard Cost Consultancy Limited | Professional & scientific | 2009 |
| MAS 2020 Ltd | Professional & scientific | 2020 |
| Matt Stanworth Golf Ltd | Arts & recreation | 2019 |
| Matthew Bailey Consulting Ltd | Professional & scientific | 2024 |
| MAW Properties (Yorkshire) Ltd | Real estate | 2026 |
| Maze Feedback UK Ltd | Information & communication | 2011 |
| MB Property Services & Developments Ltd | Construction | 2015 |
| Mcdermott Brothers Limited | Construction | 1972 |
| Mech-Pack Limited | Manufacturing | 2017 |
| Melvyn Davis Bakers Ltd | Hospitality | 2020 |
| Mepglobal Ltd | Professional & scientific | 2019 |
| Merlin Mining Limited | Financial services | 2018 |
| MHB Systems Limited | Information & communication | 2014 |
| Mick LAU Property Repairs Limited | Construction | 2004 |
| Midgley Construction Lift Support Services Limited | Construction | 2020 |
| Mike Martin Business Consultancy Limited | Professional & scientific | 2021 |
| Mitchell PUB Management Ltd | Hospitality | 2017 |
| MJT Beauty Holdings Limited | Financial services | 2026 |
| Mobile Numbers Direct Ltd | Information & communication | 2008 |
| MRC 1968 Limited | Professional & scientific | 2020 |
| MRC Propco Limited | Construction | 2024 |
| MSR Carpentry & Joinery Ltd | Construction | 2026 |
| MW Mechanical Group Ltd | Construction | 2018 |
| MW Mechanical Holdings Ltd | Administrative & support | 2018 |
| MW Mechanical LW Ltd | Administrative & support | 2018 |
| MW Mechanical SW Ltd | Construction | 2018 |
| MWS Estates Ltd | Real estate | 2021 |
| NAB International Consulting Ltd | Other services | 2024 |
| Nathan Yuill Grounds & Gardens Limited | Administrative & support | 2025 |
| NEC Maintenance Ltd | Construction | 2022 |