| Motobag Limited | Information & communication | 2026 |
| Motocut Ltd | Manufacturing | 2019 |
| Motor Mates (South Yorkshire) Limited | Wholesale & retail | 2011 |
| Motor Rush Limited | Wholesale & retail | 2022 |
| Motorcycling TV Limited | Information & communication | 2020 |
| Motore Cafe Ltd | Hospitality | 2012 |
| Motorhome Hire Yorkshire Ltd | Administrative & support | 2024 |
| Motorist DIY Limited | Wholesale & retail | 2003 |
| Motorscrubber Holdings Limited | Financial services | 2025 |
| Motorway Direct Limited | Financial services | 1996 |
| Motsoane Ltd | Transport & logistics | 2018 |
| Motspa Holdings Limited | Construction | 1970 |
| Mottainai Systems CIC | Professional & scientific | 2025 |
| Mottram and Co Limited | Extraterritorial | 2015 |
| Mould Ability Limited | Manufacturing | 2004 |
| Mouldcraft Limited | Wholesale & retail | 2017 |
| Mouldings Holdings Ltd | Real estate | 2020 |
| Mount Lebanon Limited | Hospitality | 2023 |
| Mount Pleasant Motoring Services Ltd | Wholesale & retail | 2014 |
| Mount Pleasant Park FC CIC | Arts & recreation | 2022 |
| Mount Sinai Cleaning Services Ltd | Administrative & support | 2025 |
| Mount Zion Win-Grace Ltd | Financial services | 2020 |
| Mountain Sound Ltd | Arts & recreation | 2026 |
| Mountain Therapies Ltd | Health & social care | 2023 |
| Mountain View App Ltd | Information & communication | 2026 |
| Mountelm Limited | Wholesale & retail | 1975 |
| Mountelm Reuse & Salvage Co Limited | Transport & logistics | 2012 |
| Mountmove CIC | Professional & scientific | 2023 |
| Mountox Limited | Real estate | 2026 |
| Mountrivers Ltd | Construction | 2019 |
| Mouse Protection Ltd | Administrative & support | 2025 |
| Mouv Pilates Ltd | Education | 2026 |
| Mouv Reformer Pilates Ltd | Education | 2025 |
| Mouvit Ltd | Transport & logistics | 2026 |
| Mouzakis Catering Ltd | Wholesale & retail | 2010 |
| Move ME UP Ltd | Real estate | 2024 |
| Moveboards Limited | Wholesale & retail | 2024 |
| Moventa Ltd | Wholesale & retail | 2025 |
| Moving EWE Limited | Transport & logistics | 2021 |
| MOVING4WARD Psychological Therapy Service Ltd | Health & social care | 2020 |
| Mow's Coffee Ltd | Hospitality | 2025 |
| Mowbray Manufacturing Co Limited | Manufacturing | 2018 |
| Moyasta Ltd | Construction | 2018 |
| Moyg Logistics Ltd | Transport & logistics | 2026 |
| Mozdo Ltd | Wholesale & retail | 2023 |
| Mozen Consulting Ltd | Professional & scientific | 2014 |
| MP Capital Group Ltd | Information & communication | 2025 |
| MP Capital Holdings Limited | Financial services | 2025 |
| MP Electrical Contracts Ltd | Construction | 2024 |
| MP Event Ltd | Hospitality | 2025 |
| MP Marantos Ltd | Hospitality | 2019 |
| MPD Property Maintenance Ltd | Other services | 2024 |
| MPF Risk Management Ltd | Professional & scientific | 2015 |
| MPG Construction and Development Ltd | Construction | 2017 |
| MPG Group Ltd | Construction | 1974 |
| MPG Land & Property Ltd | Real estate | 2016 |
| Mpharm Services Ltd | Health & social care | 2025 |
| Mphl 4 Ltd | Health & social care | 2025 |
| Mphl 5 Ltd | Construction | 2025 |
| Mphl 6 Ltd | Health & social care | 2025 |
| MPK Engineers Limited | Construction | 2023 |
| MPM Support Services Limited | Professional & scientific | 2016 |
| MPR Solutions Ltd | Professional & scientific | 2023 |
| Mprm Accountancy Limited | Professional & scientific | 2006 |
| MPY Limited | Real estate | 2025 |
| MR ALI Halal Butchers Ltd | Wholesale & retail | 2026 |
| MR and MRS Ice Bath Ltd | Other services | 2024 |
| MR Andrew Crookes Limited | Extraterritorial | 2025 |
| MR Bargain Beers Ltd | Wholesale & retail | 2017 |
| MR Bugg Limited | Arts & recreation | 2010 |
| MR Chai Cafe Ltd | Hospitality | 2026 |
| MR Chai Limited | Hospitality | 2023 |
| MR Chestnut Limited | Arts & recreation | 2014 |
| MR Clean Valeting Ltd | Administrative & support | 2025 |
| MR Compensator Ltd | Professional & scientific | 2013 |
| MR Construction Group Ltd | Construction | 2020 |
| MR Creams Ltd | Wholesale & retail | 2019 |
| MR D'Z Gym Ltd | Other services | 2015 |
| MR ED Productions Limited | Information & communication | 2014 |
| MR Home Improvement Ltd | Manufacturing | 2022 |
| MR Millerman Presents Ltd | Arts & recreation | 2013 |
| MR MR2 Ltd | Wholesale & retail | 2018 |
| MR Pikes Ltd | Information & communication | 2023 |
| MR Promotions UK Limited | Information & communication | 2014 |
| MR Qwak Limited | Information & communication | 2012 |
| MR S Goel Limited | Health & social care | 2011 |
| MR Smoke & Supply Ltd | Wholesale & retail | 2025 |
| MR Tea Ltd | Hospitality | 2020 |
| MR Tooze Limited | Real estate | 2023 |
| MR Vape 417 Ltd | Wholesale & retail | 2025 |
| MR Vitamins Ltd | Wholesale & retail | 2024 |
| MR Wilson's (Molly's Group) Ltd | Hospitality | 2023 |
| MR Wilson's Bar Limited | Hospitality | 2020 |
| Mr-I-Fit Ltd | Health & social care | 2025 |
| MRA Fire Safety Ltd | Professional & scientific | 2024 |
| MRB Accountancy Limited | Professional & scientific | 2014 |
| MRD Innovation Limited | Professional & scientific | 2024 |
| Mres Solutions Ltd | Information & communication | 2024 |
| MRF1905 Property Limited | Information & communication | 2016 |
| MRG Group Ltd | Hospitality | 2022 |