| Moppy Transport and Beverage Ltd | Transport & logistics | 2019 |
| More Than Digs Limited | Hospitality | 2017 |
| Morefunthanwork.Com Ltd | Other services | 2016 |
| Morgan Culture Holdings Ltd | Financial services | 2023 |
| Morpho Developments Limited | Real estate | 2021 |
| Morpho Solutions Limited | Construction | 2023 |
| Mosaic Technologies Ltd | Information & communication | 2026 |
| Mosco (Halifax) Ltd | Construction | 2025 |
| Moscovitch & Co. Limited | Other services | 2023 |
| Moseley Square Limited | Professional & scientific | 2015 |
| Moss Metal Finishing Limited | Manufacturing | 1991 |
| Moss Social Work Ltd | Health & social care | 2024 |
| Motomart Ltd | Wholesale & retail | 2024 |
| Motor Capital Ltd | Wholesale & retail | 2022 |
| Motor Proud UK Ltd | Wholesale & retail | 2021 |
| Motor Racing Publications Limited | Information & communication | 1968 |
| Motor Repair Network Ltd | Administrative & support | 2011 |
| Motor Town HX Ltd | Wholesale & retail | 2020 |
| Motorfax Car Sales Limited | Wholesale & retail | 2024 |
| Mount Packaging Software Support Ltd | Professional & scientific | 2025 |
| Mount Pellon Newsagent Ltd | Wholesale & retail | 2022 |
| Mount Vapes Limited | Wholesale & retail | 2021 |
| Mountain Air Services Limited | Real estate | 2004 |
| Mountain Motorhomes Limited | Wholesale & retail | 2021 |
| Mountain Recruitment Limited | Health & social care | 2023 |
| Mountway Holdings Limited | Wholesale & retail | 2011 |
| Mountway Limited | Manufacturing | 1981 |
| Mouse's Intelligent Computer Engineering Ltd | Information & communication | 2016 |
| MOV3MENT Ltd | Arts & recreation | 2017 |
| Moveover Limited | Construction | 2024 |
| MP Damp Proofing Services Ltd | Construction | 2023 |
| MPG Consulting Ltd | Professional & scientific | 2026 |
| MPG Investco Limited | Real estate | 2018 |
| Mpharm Alliance Ltd | Real estate | 2021 |
| Mpsc Halifax Ltd | Wholesale & retail | 2018 |
| MR Bailey's Candy Cave Limited | Wholesale & retail | 2021 |
| MR Blue HX Ltd | Wholesale & retail | 2024 |
| MR Blue R Ltd | Wholesale & retail | 2025 |
| MR Fire Prevention Ltd. | Education | 2018 |
| MR HX Ltd | Other services | 2025 |
| MR Lnks Ltd | Hospitality | 2025 |
| MR Luxe Jewellers Limited | Wholesale & retail | 2026 |
| MR Luxe Ltd | Wholesale & retail | 2024 |
| MR Pink HX Ltd | Wholesale & retail | 2025 |
| Mrhg Limited | Professional & scientific | 2019 |
| MRJ Construction (Halifax) Limited | Construction | 2020 |
| MRK VAT & Indirect Tax Consultancy Ltd | Professional & scientific | 2016 |
| MRS B'S Sandwich & Coffee HUT Limited | Hospitality | 2022 |
| MRS Leisure Services Ltd | Hospitality | 2016 |
| Mrsteelman Ltd | Wholesale & retail | 2023 |
| MRW Property Management Ltd | Real estate | 2022 |
| MS & MW Holdings Ltd | Real estate | 2025 |
| MS Beauty Services UK Limited | Other services | 2025 |
| MS Cars (Halifax) Limited | Wholesale & retail | 2014 |
| MS Cars Rental Ltd | Wholesale & retail | 2025 |
| MS Contracting (Halifax) Limited | Construction | 2020 |
| MS Holdings Private Ltd | Real estate | 2023 |
| Ms&A Healthcare Limited | Health & social care | 2018 |
| MSD Care Limited | Health & social care | 2022 |
| Msdaa Holdings Ltd | Financial services | 2025 |
| Msdaa Innovations Limited | Financial services | 2023 |
| MSE Procon Management Limited | Professional & scientific | 2021 |
| MSH Autos Ltd | Wholesale & retail | 2026 |
| MSH Property Partners Ltd | Financial services | 2025 |
| MSL Property Care Services Holdings Limited | Financial services | 2021 |
| MSL Property Care Services Limited | Administrative & support | 2007 |
| MSL Property Compliance Services Limited | Administrative & support | 2021 |
| MSL Property Services Holdings Limited | Administrative & support | 2023 |
| MSL Woodworking Machinery Limited | Manufacturing | 2002 |
| Msla Hub Ltd | Wholesale & retail | 2020 |
| MSM Property and Investments Ltd | Real estate | 2017 |
| Msmrenovations Ltd | Real estate | 2018 |
| MSN Property Rentals Ltd | Real estate | 2024 |
| Msofas Limited | Wholesale & retail | 2011 |
| Mssq Ltd | Wholesale & retail | 2012 |
| MT Cubed Limited | Financial services | 2022 |
| MT INS Limited | Financial services | 2026 |
| MU2 Electrical Limited | Construction | 2012 |
| Muff Lettings & Property Limited | Real estate | 2026 |
| Muff Properties Ltd | Real estate | 2023 |
| MUJ Transport Ltd | Transport & logistics | 2021 |
| Mullaco Halifax Ltd | Wholesale & retail | 2024 |
| Mullen Plumbing & Heating Limited | Construction | 2022 |
| Mulliner (Halifax) Limited | Professional & scientific | 2023 |
| Multi North Ltd | Professional & scientific | 2023 |
| Multi Vend Solutions Limited | Manufacturing | 2006 |
| Multiwayzz Ltd | Transport & logistics | 2025 |
| Mumonthego Limited | Professional & scientific | 2009 |
| Mums on a Mission Limited | Public administration | 2018 |
| Munder Electrical Ltd | Construction | 2023 |
| Munna Food Ltd | Hospitality | 2020 |
| Murely Digital Ltd | Wholesale & retail | 2025 |
| MUS Property Holdings Limited | Real estate | 2025 |
| Musa Builders Limited | Manufacturing | 2026 |
| Mushtaq Globalinks Ltd | Wholesale & retail | 2025 |
| Mustard & Mayo Ltd | Hospitality | 2026 |
| MWH Store Ltd | Wholesale & retail | 2025 |
| Mwita Ltd | Health & social care | 2021 |
| MWR Consulting Limited | Professional & scientific | 2005 |
| Mxgoat Ltd | Arts & recreation | 2022 |