| Leverton Gardens Management Limited | Households | 2006 |
| Lewis of Ebley Limited | Extraterritorial | 1984 |
| Lewtas Science & Technologies Ltd | Professional & scientific | 2014 |
| Lexdent Limited | Health & social care | 2019 |
| Life of Spice Ltd | Manufacturing | 2017 |
| Lilybenk 1 Limited | Real estate | 2026 |
| Lilybenk 2 Limited | Real estate | 2026 |
| Lilybenk 3 LLP | | 2026 |
| Lima Sports Ltd | Education | 2023 |
| Limito Consulting Ltd | Administrative & support | 2022 |
| Limpus Property Ltd | Real estate | 2022 |
| Lion Tree Media Ltd | Information & communication | 2023 |
| Little Fishes Nursery Limited | Health & social care | 2023 |
| Little People's Play Cafe Ltd | Hospitality | 2024 |
| Little Wild Farm Ltd | Hospitality | 2022 |
| Lizzie's Luxuries Limited | Administrative & support | 2025 |
| LJ Safety Limited | Professional & scientific | 2025 |
| Loisirs DU Maine Limited | Hospitality | 2016 |
| Lonaa Services Limited | Professional & scientific | 2025 |
| Loud Group Limited | Other services | 1999 |
| Love&Nature Ltd | Professional & scientific | 2021 |
| LR Architecture Consultancy Limited | Professional & scientific | 2011 |
| LST Property Investments Ltd | Real estate | 2021 |
| Lubs Lets Ltd | Real estate | 2025 |
| Lunanova Technologies Ltd | Professional & scientific | 2019 |
| Lusher Lawns Ltd | Construction | 2018 |
| Luxnest Homes Ltd | Real estate | 2024 |
| Luxury Nails 5 Ltd | Other services | 2023 |
| M & E Paca Properties Ltd | Real estate | 2023 |
| M C W Plumbing and Heating Ltd | Construction | 2016 |
| M J Tuckwell Ltd | Construction | 2021 |
| M V Holdings 1 Ltd | Real estate | 2020 |
| M&J Walkers Ltd | Other services | 2022 |
| M.A. Industries Limited | Professional & scientific | 2017 |
| M.M. Bellinger and Sons Limited | Wholesale & retail | 1958 |
| M.O.L.S (Oxford) Ltd | Real estate | 2018 |
| MA Surveys Ltd | Professional & scientific | 2018 |
| Maathletics Limited | Arts & recreation | 2022 |
| Mabane Ltd | Health & social care | 2016 |
| MAC4SALE Ltd | Wholesale & retail | 2017 |
| Macalder Limited | Real estate | 2008 |
| Machinations Alex Mark Limited | Manufacturing | 2024 |
| Mackenzie Creations Ltd | Manufacturing | 2026 |
| Maff and Jenny Ltd | Wholesale & retail | 2024 |
| Magdalen Road Studios | Arts & recreation | 1999 |
| Magibooks Ltd | Information & communication | 2025 |
| Magnus Oxford Ltd. | Transport & logistics | 1993 |
| Maids Causeway Holding Limited | Real estate | 2017 |
| Makosch Consulting Limited | Financial services | 2022 |
| Makosch Financial Services Limited | Financial services | 2017 |
| Makosch Property Limited | Real estate | 2017 |
| Makosch Vgdc Limited | Information & communication | 2022 |
| Mama Afrika Fashion Ltd | Wholesale & retail | 2025 |
| Management Informatics Limited | Professional & scientific | 2004 |
| Manantial Ltd | Information & communication | 2020 |
| Maniwa CY Ltd | Real estate | 2013 |
| Manor Bespoke Joinery Limited | Construction | 2025 |
| Manor Flooring Limited | Construction | 2009 |
| Manor Properties Lechlade Limited | Real estate | 2011 |
| Mapnik Consulting Limited | Information & communication | 2014 |
| Marc Anthony Bathrooms Ltd | Construction | 2022 |
| Margaret O'Rorke Lighting Limited | Manufacturing | 2015 |
| Maridadi Ltd | Professional & scientific | 2023 |
| Mario Plumbing Ltd | Construction | 2022 |
| Marius Catalin Hojda Limited | Transport & logistics | 2017 |
| Mark in the Media Ltd | Information & communication | 2023 |
| Mark Weston Associates Limited | Administrative & support | 2023 |
| Marley Close Management Company Limited | Households | 2013 |
| Marlin Land Investments Ltd | Construction | 2025 |
| Marrakesh Records LLP | | 2025 |
| Marshalls Carpentry & Services Ltd | Construction | 2024 |
| Marval Mendoza Limited | Health & social care | 2022 |
| Maryon Bros Construction Limited | Construction | 2019 |
| Masonry Medic Limited | Construction | 2011 |
| Masons Court Management Company NO.2 Limited | Households | 2011 |
| Masterfit Joinery Limited | Construction | 2025 |
| Matrixtake Ltd | Professional & scientific | 2026 |
| Matsho Enterprises Limited | Wholesale & retail | 2014 |
| Matthews Land Group Ltd | Administrative & support | 2005 |
| Mattingley Limited | Water & waste | 2009 |
| Maukbs (UXB) Limited | Manufacturing | 2012 |
| Maukbs Limited | Manufacturing | 2010 |
| Maukbs Real Estate Limited | Real estate | 2020 |
| Maverick Corp Holdings Ltd | Administrative & support | 2026 |
| Maybec Properties Limited | Professional & scientific | 2016 |
| Maymessy Community Interest Company | Education | 2015 |
| MBR Beauty Ltd | Other services | 2021 |
| MC Falcon Investments UK Limited | Real estate | 2014 |
| MC HCA Ltd | Health & social care | 2020 |
| Mccarthy & Co Holdings Ltd | Real estate | 2021 |
| Mccarthy Discovery Solutions Limited | Professional & scientific | 2015 |
| Mclongstop Limited | Real estate | 2010 |
| MCW Dividers Ltd | Wholesale & retail | 2024 |
| MD Contracting Ltd | Manufacturing | 2019 |
| MDC MAX Daetwyler U.K. Limited | Wholesale & retail | 1982 |
| Meisterstueck-Haus UK Limited | Construction | 2025 |
| Melosens Ltd | Information & communication | 2025 |
| Memories Unlimited Limited | Professional & scientific | 2011 |
| Mercure Counselling & Training Alliance CIC | Public administration | 2021 |
| Meritum Property Limited | Real estate | 2025 |