| Maritime Business Park (Hessle) Limited | Financial services | 2025 |
| Markleehairandskin Ltd | Other services | 2023 |
| Marlin Communication Services Ltd | Information & communication | 2010 |
| Marmoz Ltd | Hospitality | 2020 |
| Marne Kitchen Ltd | Hospitality | 2019 |
| Marquest Limited | Information & communication | 1994 |
| Marrett & Taylor Ltd | Construction | 2020 |
| Marrett and Taylor Maintenance Ltd | Construction | 2022 |
| Marsforth Limited | Financial services | 2020 |
| Marsh & Milburn Ltd | Hospitality | 2023 |
| Martec UK Trading Ltd | Wholesale & retail | 2025 |
| Martin James Fahy Financial Planning Limited | Financial services | 2024 |
| Marwood & Shepherd Ltd | Wholesale & retail | 2014 |
| Mary Gannon Design Ltd | Administrative & support | 2009 |
| Mascott's Farm Ltd | Agriculture & fishing | 2001 |
| Mascotte Gardens Limited | Households | 1994 |
| Masum Grill House Limited | Hospitality | 2019 |
| Matz Limited | Professional & scientific | 2016 |
| Mayfair Apartments Ltd | Real estate | 2013 |
| Mayfair Lettings (Hull) Limited | Real estate | 2015 |
| Mayfair Property (Hull) Limited | Real estate | 2015 |
| Mazeys Ltd | Administrative & support | 2021 |
| Mcclane Materials Handling Training Ltd | Education | 2021 |
| Mciver Property Holdings Limited | Financial services | 2026 |
| MCS Heating and Plumbing Limited | Professional & scientific | 2003 |
| Mcvi Property Limited | Real estate | 2019 |
| ME 2 U Therapeutic Services CIC | Health & social care | 2025 |
| Meadow Cottage Developments Limited | Construction | 2024 |
| Meadow Oral Care Ltd | Health & social care | 2025 |
| Meadow Property Co Limited | Construction | 2008 |
| Medicopharm Limited | Health & social care | 2010 |
| Mediretail Limited | Wholesale & retail | 2024 |
| Meliora Kittens Ltd | Agriculture & fishing | 2024 |
| Mellcon Limited | Construction | 2021 |
| Mellifera Meadery Limited | Manufacturing | 2023 |
| Melworth Properties Limited | Households | 1984 |
| MEM Associates Limited | Health & social care | 2023 |
| Mentis Clinic Ltd. | Health & social care | 2022 |
| Meow KIM Ltd | Hospitality | 2026 |
| Mere Glen Management Company Limited | Extraterritorial | 2012 |
| Mere View Hornsea Management Company Limited | Households | 2022 |
| Merlan Ltd | Information & communication | 2018 |
| Mertech Electrical Limited | Construction | 2014 |
| Mertech Ltd | Construction | 2010 |
| Meryem HF Ltd | Hospitality | 2025 |
| Metal Herring Ltd | Manufacturing | 2023 |
| Mettyear Consulting Limited | Professional & scientific | 2017 |
| Meza 9 Limited | Construction | 2007 |
| MG Lifting Ltd | Construction | 2018 |
| MGS Beverley Ltd | Administrative & support | 2021 |
| Michael Anthony Burton Ltd | Extraterritorial | 2023 |
| Michael Glover Limited Liability Partnership | | 2001 |
| Michael Pellen Limited | Health & social care | 2014 |
| Middlehowe Farms Ltd | Agriculture & fishing | 2017 |
| Midgard Games Ltd | Wholesale & retail | 2022 |
| Migee Properties Ltd | Real estate | 2024 |
| Mike AI Ltd | Information & communication | 2024 |
| Mike East Funeral Directors Limited | Other services | 2013 |
| Mike Kemp (Beverley) Limited | Other services | 2013 |
| Mike Ltd | Extraterritorial | 2016 |
| Mike Media Ltd | Extraterritorial | 2016 |
| Milburn Concrete Pumping Ltd | Construction | 2017 |
| Miles Kader Ltd | Wholesale & retail | 2026 |
| Milestone Fitness Ltd | Arts & recreation | 2020 |
| Mill Lane Auto Limited | Wholesale & retail | 2000 |
| Millarry Investments Ltd | Real estate | 2024 |
| Millbeck Management Company Limited | Real estate | 1987 |
| Millennium Express Ltd | Manufacturing | 2016 |
| Millennium Mortgages Limited | Financial services | 2009 |
| Miller-Eyre Construction Ltd | Construction | 1992 |
| Millers Building & Roofing Limited | Construction | 2007 |
| Minerva Legal Limited | Professional & scientific | 2014 |
| Minmore House Hotel Limited | Hospitality | 1986 |
| Minster Barber Ltd | Other services | 2025 |
| Minster Beverley Limited | Wholesale & retail | 2014 |
| Minster Blinds Limited | Construction | 2023 |
| Minster Business Services Ltd | Professional & scientific | 2022 |
| Minster Court (Yorkshire) RTM Company Limited | Extraterritorial | 2015 |
| Minster Court Flats(Hull)Limited | Households | 1965 |
| Minster Cycles Limited | Wholesale & retail | 2025 |
| Minster Financial Limited | Financial services | 2021 |
| Minster Financial Management Limited | Financial services | 2003 |
| Minster Land Investments Limited | Real estate | 2025 |
| Minster Laundry & Ironing Ltd | Information & communication | 2015 |
| Minster Leisure Homes Ltd | Manufacturing | 2020 |
| Minster Management Limited | Real estate | 2024 |
| Minster Paving and Landscapes Ltd | Construction | 2021 |
| Minster Surveying Limited | Professional & scientific | 2014 |
| Minster View Properties Limited | Real estate | 1982 |
| Minster Yard South Limited | Real estate | 2020 |
| Miota Kepsilon Capital Limited | Education | 2020 |
| Miss Buffet Ltd | Hospitality | 2012 |
| Miss Elles Design Florists Limited | Wholesale & retail | 2008 |
| Miss Rachael's School of Dance Limited | Arts & recreation | 2014 |
| Mission Sports Management Limited | Professional & scientific | 2001 |
| Missko Limited | Information & communication | 2001 |
| MJ Grant Financial Planning Ltd | Professional & scientific | 2023 |
| MJ Insource 1ST Group Ltd | Financial services | 2023 |
| MJC White Smile Ltd | Health & social care | 2026 |
| MJP Rentals Ltd | Households | 2023 |