| LP Reach Ltd | Professional & scientific | 2025 |
| LSW Workshop Supplies Limited | Other services | 2003 |
| Lucy Bailey Consulting Limited | Professional & scientific | 2025 |
| Ludol Consulting Ltd | Professional & scientific | 2021 |
| Luke Bowers Barbershop Ltd | Other services | 2026 |
| Luntrus Trans Ltd | Administrative & support | 2016 |
| LUX Industries Ltd | Professional & scientific | 2022 |
| Luxore Beauty UK Ltd | Other services | 2024 |
| Luxury House Oxford LLP | | 2024 |
| LVW Limited | Information & communication | 2025 |
| Lw&E Investments Ltd | Real estate | 2025 |
| M & J Didcock Funeral Service Ltd | Other services | 2021 |
| M C E C & I Ltd | Construction | 2017 |
| M Stock Plumbing & Heating Ltd | Construction | 2013 |
| M&A Consultations Ltd | Professional & scientific | 2022 |
| M.L. Blakeman Plumbing & Heating Services Ltd | Construction | 2019 |
| M.Sutton Consulting Limited | Professional & scientific | 2016 |
| M2M Tech Limited | Manufacturing | 2014 |
| MA Pharma Consulting Ltd | Professional & scientific | 2025 |
| Maapss Ltd | Real estate | 2025 |
| Macdonald Family Office Ltd | Financial services | 2026 |
| Machine Vision Developments Ltd | Real estate | 2025 |
| Mack SCI Solutions Ltd | Professional & scientific | 2024 |
| Macusteron Ltd | Manufacturing | 2014 |
| Madhu Kitchen Ltd | Hospitality | 2025 |
| Magdalen Holdings Ltd | Real estate | 2025 |
| Mahmoud Trade Limited | Financial services | 2025 |
| Maisaku Limited | Hospitality | 2025 |
| Makepeace and Massage Ltd | Education | 2020 |
| Maltora Engineering Ltd | Information & communication | 2025 |
| Mamma Cubs Limited | Health & social care | 2020 |
| MAN Down Charity UK Ltd | Health & social care | 2023 |
| Manifest Health Limited | Wholesale & retail | 2004 |
| Mans Tech Ltd | Wholesale & retail | 2018 |
| Mapleisland Ltd | Wholesale & retail | 2021 |
| Mar's Properties Management Ltd | Real estate | 2021 |
| Marble Air Ltd | Professional & scientific | 2017 |
| Marian Davidson Landscape Design Ltd | Administrative & support | 2026 |
| Marked Consulting Limited | Education | 2022 |
| Marm Properties Limited | Real estate | 2024 |
| Mars Society | Professional & scientific | 2018 |
| Marsdengray Limited | Administrative & support | 2013 |
| Marshgate Assets Ltd | Real estate | 2025 |
| Martin Teasdale Ltd | Information & communication | 2021 |
| Mary Kennedy House Freehold Residents Management Ltd | Households | 2024 |
| Marz Associates Ltd | Real estate | 2025 |
| Masterweld Equipment (UK) Ltd | Manufacturing | 2014 |
| Matchtech Ltd | Administrative & support | 2026 |
| Materna Tea Ltd | Wholesale & retail | 2025 |
| Maysfair Lettings Ltd | Real estate | 2025 |
| Mbms Systems Limited | Wholesale & retail | 2011 |
| Mccarron Homes Ltd | Real estate | 2022 |
| MCM Tech Support Services Ltd | Information & communication | 2024 |
| MCT Multi-Trade Ltd | Manufacturing | 2025 |
| MCT Online Limited | Arts & recreation | 2022 |
| Md-Tr Ltd | Transport & logistics | 2023 |
| MDA Digital Communications Ltd. | Manufacturing | 2018 |
| MDA Space and Robotics Limited | Professional & scientific | 2005 |
| Medicalar Ltd | Education | 2021 |
| MEI Property Ltd | Real estate | 2025 |
| Meili GPS Limited | Information & communication | 2018 |
| Meisaku Limited | Hospitality | 2025 |
| Meltz Oxford Limited | Real estate | 2006 |
| MEM Solutions Ltd | Construction | 2019 |
| Memoa Ltd | Information & communication | 2025 |
| MEP Acad Services Limited | Public administration | 2014 |
| Meraki Analytical Solutions Limited | Information & communication | 2022 |
| Meraki Crafts Studio Limited | Wholesale & retail | 2022 |
| Merladona Trading (UK) Ltd. | Wholesale & retail | 2014 |
| Merlin Grace Capital Limited | Financial services | 2026 |
| Meta Futura Aerospace Ltd | Manufacturing | 2024 |
| Metinn Consultancy Limited | Professional & scientific | 2026 |
| MGM Grand Decorators Ltd | Construction | 2024 |
| Mhcarpentry and Construction Limited | Construction | 2011 |
| MHS Accounting Services Limited | Professional & scientific | 2002 |
| Mick Bond Limited | Construction | 2014 |
| Mickelian Ltd | Information & communication | 2021 |
| Microbesphere Ltd | Professional & scientific | 2019 |
| Microcorem Ltd | Information & communication | 2026 |
| Micronano Systems Limited | Manufacturing | 2013 |
| Mike Smith Associates Limited | Administrative & support | 2002 |
| Milmur Ltd | Real estate | 2023 |
| Miltenberger Cyro Services Limited | Administrative & support | 2001 |
| Mind Tech Consultancy Ltd | Information & communication | 2018 |
| Mindtrest Ltd | Information & communication | 2026 |
| Minerva Blue Limited | Real estate | 2025 |
| Mining IP Limited | Professional & scientific | 2013 |
| Mirico Ltd. | Manufacturing | 2015 |
| Mirroring Minds Ltd | Health & social care | 2023 |
| Mission Burrito Ltd | Hospitality | 2020 |
| Mistral Engineering Limited | Professional & scientific | 2021 |
| Mjam Limited | Mining & quarrying | 2003 |
| Mjjbn Ltd | Real estate | 2025 |
| MK Heating Solutions Ltd | Construction | 2024 |
| Mkss Services Ltd | Wholesale & retail | 2018 |
| ML Blakeman Heating & Renewables Ltd | Construction | 2025 |
| MLN Property Investments Ltd | Real estate | 2024 |
| MM Motors Didcot Limited | Wholesale & retail | 2023 |
| MMC Assets Ltd | Real estate | 2026 |
| MME Building Solutions Ltd | Construction | 2023 |