| MLW Electrical Inspection Services Ltd | Construction | 2017 |
| MM Accountancy Solutions Limited | Professional & scientific | 2013 |
| MMB Consulting Ltd | Information & communication | 2007 |
| Mmbelectrical Ltd | Energy | 2020 |
| MMC Humber Ltd | Professional & scientific | 2025 |
| Mmpg Limited | Financial services | 2019 |
| MN Cabs Ltd | Transport & logistics | 2025 |
| MN Transport Limited | Transport & logistics | 2024 |
| Mo&M 75 Limited | Other services | 2017 |
| Mobay Trading Ltd | Wholesale & retail | 2025 |
| Mobi World Ltd | Wholesale & retail | 2022 |
| Mobibrain Limited | Information & communication | 2010 |
| Mobile Medical Cover Ltd | Health & social care | 2012 |
| Mobile PAY Ltd | Other services | 2024 |
| Mobile Truck & Trailer Limited | Manufacturing | 2006 |
| Mobius Wealth Ltd. | Professional & scientific | 2019 |
| Modal Training Ltd | Education | 1998 |
| Modern Matriarchs CIC | Health & social care | 2025 |
| Modestoh Property Management Ltd | Real estate | 2024 |
| Modus 4U Ltd | Construction | 2016 |
| Modus Recycling C.I.C. | Water & waste | 2017 |
| Mohandison Limited | Real estate | 2025 |
| Mollyabs.Coaching Limited | Education | 2025 |
| MOMCHI74 Ltd | Transport & logistics | 2018 |
| Monarc Services Ltd | Manufacturing | 2021 |
| Monarch Thread and Fabric Limited | Wholesale & retail | 2026 |
| Monarro Limited | Professional & scientific | 2019 |
| Monday's Child Aesthetics Ltd | Other services | 2018 |
| Moneymerge Limited | Financial services | 2007 |
| Moneypenny Recruitment Ltd | Administrative & support | 2018 |
| Monique's Estate Agency Limited | Real estate | 2023 |
| Mono Tea Limited | Hospitality | 2022 |
| Moodstrings Limited | Wholesale & retail | 2025 |
| Moody International Refrigeration Limited | Wholesale & retail | 2006 |
| Moon Under Water Limited | Manufacturing | 2019 |
| Moonfleet Marine Ltd | Manufacturing | 2023 |
| Moonlight Organisation Ltd | Hospitality | 2025 |
| Moonraker (MFG) Ltd | Manufacturing | 2021 |
| Moorcroft Seafoods Limited | Wholesale & retail | 2009 |
| Moore Construction Management Ltd | Construction | 2018 |
| Moore Roofing (Grimsby) Limited | Construction | 2025 |
| Moore-Bannon Limited | Professional & scientific | 2022 |
| More Choice Limited | Information & communication | 2014 |
| More Space (Lincs) Limited | Construction | 2014 |
| Morgans Hairdressers Limited | Other services | 2023 |
| Morjana Pharma Ltd | Health & social care | 2023 |
| Morland Services UK Ltd | Administrative & support | 2017 |
| Morning Campers Ltd | Construction | 2026 |
| Morosanu ADM Ltd | Transport & logistics | 2024 |
| Morrison Software Ltd | Information & communication | 2014 |
| Mortez Ltd | Hospitality | 2025 |
| Mosaic Compliance Solutions Limited | Financial services | 2017 |
| Moss Agate Limited | Administrative & support | 2014 |
| MOT & Vehicle Operator Consultancy (England) Limited | Transport & logistics | 2013 |
| Mothership Dance CIC | Arts & recreation | 2026 |
| Motina Limited | Administrative & support | 2019 |
| Motina Properties and Maintenance Ltd | Real estate | 2024 |
| Motor Mate Limited | Wholesale & retail | 2010 |
| Motorcycle Smart Garage Ltd | Wholesale & retail | 2024 |
| Mould Solution Grimsby Limited | Construction | 2026 |
| Mount Olive (UK) Limited | Hospitality | 1999 |
| Mount Plumbing Limited | Construction | 2017 |
| Mourik U.K. Limited | Professional & scientific | 1989 |
| Mower Services Grimsby Limited | Wholesale & retail | 2024 |
| MP Heavy Lifting Services Ltd | Construction | 2024 |
| MP Marco Ltd | Transport & logistics | 2020 |
| Mpbc Haulage Ltd | Transport & logistics | 2025 |
| MPK Logistic Ltd | Transport & logistics | 2018 |
| MPM Transport Services Ltd | Transport & logistics | 2023 |
| MPR Building Services (GY) Ltd | Construction | 2019 |
| MPR Developments Ltd | Real estate | 2016 |
| MPS (Grimsby) Ltd | Transport & logistics | 2015 |
| MPS Maintenance Engineering Limited | Manufacturing | 2014 |
| MPS Plumbing & Drainage Ltd | Other services | 2004 |
| Mpvs Limited | Wholesale & retail | 2004 |
| MR Chicken & Pizzeria Ltd | Hospitality | 2025 |
| MR Compliance & Training Ltd | Education | 2025 |
| MR Exhaust & Tyre Centre Ltd | Wholesale & retail | 2024 |
| MR Lazzolli's BBQ Ltd | Hospitality | 2026 |
| MR Nice Inc Ltd | Wholesale & retail | 2020 |
| MR Residential Property Ltd | Real estate | 2026 |
| Mrdi Associates Limited | Health & social care | 2015 |
| MRG Testing Ltd | Transport & logistics | 2018 |
| MRM Construction Ltd | Construction | 2019 |
| Mrmmbs Vision Ltd | Information & communication | 2019 |
| MRO Plus Solutions Group Ltd | Financial services | 2017 |
| MRO Plus Solutions Midco Ltd | Financial services | 2017 |
| MRO+ Solutions Ltd | Financial services | 2017 |
| MRT Investments Ltd | Real estate | 2019 |
| MRW Electrical Limited | Construction | 2007 |
| MS Property (Cleethorpes) Ltd | Real estate | 2024 |
| MS Property Trading Solutions Ltd | Real estate | 2022 |
| MS Protection Ltd | Financial services | 2024 |
| MS Vision Group Ltd | Wholesale & retail | 2025 |
| MS1985 Limited | Construction | 2015 |
| MS97 Properties Limited | Real estate | 2023 |
| MSB Wholesale Services Limited | Wholesale & retail | 2016 |
| Mscw Cars Limited | Administrative & support | 2025 |
| MSK Trans Ltd | Transport & logistics | 2019 |
| MSP Accounts Ltd | Professional & scientific | 2021 |