| Mpljll Limited | Other services | 2024 |
| MPM Building Services Consultants Ltd | Professional & scientific | 2023 |
| MPM Logistics Limited | Transport & logistics | 2025 |
| Mpro Communication Ltd | Information & communication | 2022 |
| MPS Harworth Limited | Wholesale & retail | 2021 |
| MR & MRS Pickwick's Ltd | Hospitality | 2016 |
| MR and MJ Properties Limited | Administrative & support | 2017 |
| MR and MRS Caterpillars Limited | Manufacturing | 2016 |
| MR Auto Garage Ltd | Wholesale & retail | 2023 |
| MR Baig Ltd | Construction | 2024 |
| MR Blue One Limited | Wholesale & retail | 2025 |
| MR Consulting Limited | Professional & scientific | 2022 |
| MR D Noonan & MRS R SO LLP | | 2012 |
| MR DAN Team Ltd | Education | 2018 |
| MR Engineering Ltd | Professional & scientific | 2022 |
| MR Garage Ltd | Wholesale & retail | 2022 |
| MR Grill Ltd | Transport & logistics | 2024 |
| MR H Angel Limited | Hospitality | 2017 |
| MR Hottubs Limited | Administrative & support | 2003 |
| MR MC Limited | Administrative & support | 2023 |
| MR Motor-Vated Ltd | Wholesale & retail | 2026 |
| MR Pipes Ltd | Professional & scientific | 2011 |
| MR Singhs the Little Shop Ltd | Wholesale & retail | 2025 |
| MR Wu’S Golden COD Ltd | Hospitality | 2026 |
| Mr-Joy Ltd | Wholesale & retail | 2020 |
| MR. Tony for Hair Limited | Other services | 2014 |
| MRB Plant & Haulage Ltd | Transport & logistics | 2014 |
| MRD Decorating & Property Services Ltd | Construction | 2025 |
| Mrdkfw Limited | Professional & scientific | 2012 |
| Mrkai Holdings Limited | Extraterritorial | 2025 |
| MRL Joinery Limited | Construction | 2021 |
| MRL Spedition Ltd | Transport & logistics | 2025 |
| MRM Leisure Limited | Professional & scientific | 2003 |
| MRO Associates Ltd | Professional & scientific | 2011 |
| MRP Automotive (Yorkshire) Limited | Wholesale & retail | 2023 |
| MRR & BVA Limited | Transport & logistics | 2018 |
| MRS J - Making Memories Ltd | Manufacturing | 2025 |
| Mrsmac Ltd | Wholesale & retail | 2018 |
| MS Alliance Ltd | Wholesale & retail | 2022 |
| MS Detailing Ltd | Wholesale & retail | 2021 |
| MS International Estates Limited | Real estate | 2018 |
| MS International PLC | Professional & scientific | 1960 |
| MS Medicals Limited | Health & social care | 2020 |
| MS Reporting Ltd | Other services | 2025 |
| MSC Property Estates Ltd | Real estate | 2018 |
| MSC Trade Contractors Limited | Construction | 2017 |
| MSH Landmark Properties Limited | Administrative & support | 2025 |
| MSI Logistics Limited | Transport & logistics | 2026 |
| Msjj Consulting Limited | Professional & scientific | 2010 |
| MSM 17 Ltd | Wholesale & retail | 2018 |
| MSM Civils Limited | Professional & scientific | 2019 |
| MSN Limited | Construction | 2015 |
| MST Property Management Limited | Real estate | 2003 |
| MSW Development Yorkshire Ltd | Construction | 2024 |
| MSW Property Investment Ltd | Real estate | 2024 |
| MT Bubbles Ltd | Information & communication | 2025 |
| MT Motorcycles Limited | Wholesale & retail | 2002 |
| MT York Limited | Administrative & support | 2015 |
| MT. Kailash Homes Limited | Real estate | 2024 |
| Mtek Management Limited | Professional & scientific | 2018 |
| MTM AMO Ltd | Transport & logistics | 2025 |
| MTM13 Ltd | Transport & logistics | 2019 |
| Mtnt Transport Ltd | Transport & logistics | 2022 |
| MTR Electrical Services Limited | Construction | 2019 |
| MTS Brickwork Limited | Construction | 2025 |
| MTS Software Limited | Information & communication | 2021 |
| Mtsinclair Ltd | Other services | 2020 |
| Mtswakayi Ltd | Health & social care | 2014 |
| Mtuitive UK Limited | Information & communication | 2018 |
| Mucky Paws Medical Ltd | Health & social care | 2023 |
| Mufaro Air &Sea Logistics Ltd | Transport & logistics | 2025 |
| Mughal Property Investments Limited | Real estate | 2024 |
| Mugoni Limited | Health & social care | 2021 |
| Mukanya Logistics International Ltd | Transport & logistics | 2024 |
| Mulberry Accounting Services Limited | Professional & scientific | 2002 |
| Mulberry Interiors (Doncaster) Ltd | Construction | 2009 |
| Mulberry Park Management Co. Limited | Households | 1995 |
| Mulberry Properties Doncaster Ltd | Real estate | 2025 |
| Mulberry Rooms Limited | Other services | 2023 |
| Mulhall's Business Services Ltd | Extraterritorial | 2017 |
| Mullen Homes Limited | Hospitality | 2003 |
| Mullen Rentals Limited | Real estate | 2019 |
| Multi-Web-Services.Co.Uk Limited | Information & communication | 2013 |
| Multi-Weld UK Limited | Manufacturing | 2009 |
| Multiflow Systems Limited | Wholesale & retail | 1995 |
| Multitrack Electrical Limited | Professional & scientific | 2019 |
| Mumbai the Restaurant Ltd | Hospitality | 2017 |
| Mummyfit (South Yorkshire) Ltd | Arts & recreation | 2019 |
| Munchez Limited | Hospitality | 2018 |
| Munchez Street Bites Ltd | Hospitality | 2025 |
| Munda Healthcare Services Limited | Health & social care | 2017 |
| Munda Travel Limited | Transport & logistics | 2025 |
| Munechild Limited | Professional & scientific | 2019 |
| Munivy Care Ltd | Health & social care | 2024 |
| Munro Developments Ltd | Construction | 2021 |
| Murbridge Lettings Ltd | Households | 2025 |
| Muresan Transport Ltd | Transport & logistics | 2018 |
| Murgatroyd Opticians Limited | Wholesale & retail | 2002 |
| Murphy's Sports Bar Limited | Hospitality | 2020 |
| Murray Resources Ltd | Construction | 2018 |