| Miriam Clark Ventures Ltd | Real estate | 2025 |
| Mirror Signal Manoeuvre Limited | Education | 2019 |
| Misfit Media Limited | Information & communication | 2014 |
| Misha Family Holdings Ltd | Financial services | 2025 |
| Mishou Ltd | Real estate | 2022 |
| Misior Logistics Limited | Transport & logistics | 2016 |
| Miskil Ltd | Hospitality | 2024 |
| Miss Moss Publishing Ltd | Information & communication | 2024 |
| Mister Freeman Limited | Construction | 2020 |
| Misu Transport Ltd | Transport & logistics | 2020 |
| Mitchell Belk Ltd | Professional & scientific | 2018 |
| Mitchell Groundworks Ltd | Construction | 2012 |
| Mitchell Management Company Limited | Real estate | 1983 |
| Mitchell Transformers Limited | Manufacturing | 1970 |
| Mithril Industries Ltd | Information & communication | 2025 |
| Miznon Ltd | Hospitality | 2019 |
| MJ Automobile Ltd | Wholesale & retail | 2013 |
| MJ Landscape Limited | Administrative & support | 2017 |
| MJ Marine Ltd | Manufacturing | 2023 |
| MJ Properties (South) Ltd | Real estate | 2023 |
| MJ Property (Bournemouth) Ltd | Real estate | 2017 |
| MJ24 Limited | Real estate | 2017 |
| MJC Home Services Ltd | Other services | 2018 |
| Mjhs Mortgages Limited | Financial services | 2022 |
| Mjkm-Trans Ltd | Transport & logistics | 2021 |
| MJL Properties (Hampshire) Holdings Limited | Professional & scientific | 2011 |
| MJL Properties (Hampshire) Limited | Real estate | 2011 |
| MJO Investments Limited | Real estate | 2016 |
| MJP Driveways Limited | Construction | 2023 |
| MJP Systems Engineering Limited | Administrative & support | 2024 |
| MJW Rentals & Services Ltd | Construction | 2025 |
| MK Building Solutions Ltd | Construction | 2024 |
| MK C Properties (Bmth) Limited | Real estate | 2020 |
| MK Cargo Partner Ltd | Administrative & support | 2014 |
| MK Carpentry Technique Limited | Construction | 2018 |
| MK Composites Ltd | Manufacturing | 2022 |
| MK Estates - Holdenhurst Road Limited | Real estate | 2016 |
| MK Interiors & Kitchens Ltd | Manufacturing | 2017 |
| MK Lettings 4U Ltd | Real estate | 2026 |
| MK Plumbing Dorset Ltd | Construction | 2019 |
| MK Servicing Ltd | Manufacturing | 2023 |
| MK Sphere Investments Limited | Real estate | 2022 |
| MK Structures Limited | Administrative & support | 2007 |
| MK1 Plumbing Services Ltd | Construction | 2014 |
| MKC Carpentry Ltd | Construction | 2022 |
| Mkcompany Ltd | Transport & logistics | 2018 |
| MKD Property Surveying Ltd | Professional & scientific | 2025 |
| Mkdh Ltd | Information & communication | 2013 |
| MKG Digital Ltd | Professional & scientific | 2023 |
| MKL Enterprises Ltd | Wholesale & retail | 2019 |
| MKS Plastering Limited | Construction | 2018 |
| ML Quality Home Improvements Ltd | Construction | 2020 |
| MLH Water Sports Limited | Wholesale & retail | 2026 |
| MLS Motors Limited | Wholesale & retail | 2024 |
| MLW Land & New Homes Limited | Construction | 2022 |
| MM Kitchen Services Ltd | Construction | 2024 |
| MMA Fight Night Limited | Arts & recreation | 2017 |
| MME Heating & Plumbing Ltd | Construction | 2021 |
| MMF Properties Ltd | Real estate | 2018 |
| Mmhrope Limited | Wholesale & retail | 2018 |
| MNJ Productions Limited | Arts & recreation | 2009 |
| Mobile Brakes & Tyres Ltd | Wholesale & retail | 2017 |
| Mobile Radio Cars Limited | Transport & logistics | 2019 |
| Mobile Tyres Portsmouth Limited | Wholesale & retail | 2025 |
| Mobilephonexpert Ltd | Wholesale & retail | 2018 |
| Mobility and Staffing Ltd | Transport & logistics | 2025 |
| Mockbeggar Properties Limited | Construction | 2004 |
| Model Ideas Limited | Professional & scientific | 2011 |
| Model Rail UK Limited | Manufacturing | 2021 |
| Model Railway Solutions Limited | Arts & recreation | 2017 |
| Modern Light Cars Ltd | Wholesale & retail | 2015 |
| Modular Care Unit Limited | Construction | 2015 |
| Modular Hydraulic Systems Limited | Manufacturing | 1978 |
| Moejo Creations Ltd | Wholesale & retail | 2021 |
| Mogok Red Ltd | Wholesale & retail | 2026 |
| Mohamz Sales Limited | Wholesale & retail | 2024 |
| Mohapisekamano Ltd | Administrative & support | 2016 |
| Moho Technologies Ltd | Information & communication | 2025 |
| Mohsini Estates Ltd | Real estate | 2025 |
| Mohtiv Ltd | Professional & scientific | 2016 |
| Moina Properties Ltd | Real estate | 2025 |
| Moirai Management Limited | Professional & scientific | 2015 |
| Moka Properties Ltd | Real estate | 2022 |
| Moldhome Ltd | Real estate | 2020 |
| Molecular Magic Creative Catering Ltd | Hospitality | 2019 |
| Molecular Magic Events Limited | Hospitality | 2025 |
| Molecure Limited | Manufacturing | 2024 |
| Momaty BP1 Ltd | Real estate | 2018 |
| Momaty Homes Limited | Real estate | 2017 |
| Momaty Properties Limited | Construction | 2006 |
| Momently Ltd | Professional & scientific | 2026 |
| Momentum Studio Ltd | Professional & scientific | 2025 |
| Mona Rosa Ltd | Wholesale & retail | 2021 |
| Monarch Global Limited | Construction | 2005 |
| Monarch Hub Ltd | Administrative & support | 2022 |
| Monarch Mead Limited | Wholesale & retail | 2025 |
| Monatech Limited | Wholesale & retail | 2022 |
| Monceau Group Ltd | Administrative & support | 2026 |
| Monday Movie Ltd | Information & communication | 2026 |
| Mondo SZ Ltd | Administrative & support | 2018 |