| Masuta Geijutsu Ltd | Extraterritorial | 2024 |
| Mathew Derbyshire Limited | Financial services | 2021 |
| Mathew FOX Ltd | Transport & logistics | 2014 |
| Matrix Logic Comnet Limited | Information & communication | 1987 |
| Mats Property Group Ltd | Real estate | 2024 |
| Matsawmar Ltd | Administrative & support | 2020 |
| Matt Horbury Limited | Professional & scientific | 2013 |
| Mattercrafted 3D Ltd | Manufacturing | 2025 |
| Mattherson Ltd | Hospitality | 2025 |
| Matthew Thickett Limited | Other services | 2003 |
| Maximum (Escapes) Ltd | Hospitality | 2021 |
| Maximum Octopus Limited | Information & communication | 2014 |
| Maxseller Ltd | Wholesale & retail | 2016 |
| Maya Beauty Salon Limited | Wholesale & retail | 2024 |
| Mayfield (Washington) Management Company Limited | Households | 1997 |
| Mayfields Property Investments Limited | Real estate | 2016 |
| Mayor Healthcare Ltd | Health & social care | 2024 |
| Maypole Brewery Limited | Manufacturing | 2005 |
| Maypole Brewing Company Ltd | Manufacturing | 2024 |
| Mayward Farm Management Limited | Households | 2025 |
| Mbailey Plumbing & Heating Ltd | Construction | 2025 |
| MBM Management Services Limited | Real estate | 2020 |
| MC Project Solutions Limited | Construction | 2015 |
| MCB Brothers Limited | Administrative & support | 1999 |
| Mccallum Pubs Ltd | Hospitality | 2021 |
| Mcclelland House Management Limited | Households | 2005 |
| Mcconnells Electrical Company Limited | Construction | 1991 |
| Mcconnells Electrical Services Limited | Construction | 1999 |
| Mcfarlane Media Limited | Arts & recreation | 2025 |
| MCG Business Consultants Limited | Professional & scientific | 2011 |
| Mcguirk Electrical Limited | Professional & scientific | 2019 |
| Mchair Limited | Other services | 2016 |
| Mcilroy Associates Limited | Administrative & support | 2009 |
| Mcintyre Assessment Ltd | Professional & scientific | 2015 |
| Mckenzie's Digital Assets Investments Limited | Financial services | 2025 |
| MCL Marketing Consultancy Limited | Professional & scientific | 2016 |
| MCM Care Limited | Public administration | 2025 |
| Mcmanus Supported Living Limited | Health & social care | 2018 |
| MCR Joinery Limited | Construction | 2009 |
| MDB International Holdings Limited | Financial services | 2020 |
| MDG Bespoke Beauty Ltd | Other services | 2019 |
| MDL Wholesale Ltd | Wholesale & retail | 2022 |
| Meadow Energies Limited | Energy | 2021 |
| Meadow Energy Limited | Real estate | 2021 |
| Meatsmiths Ltd | Wholesale & retail | 2011 |
| Mechanical Solutions Limited | Manufacturing | 2001 |
| Meden Transport Ltd | Transport & logistics | 2021 |
| Medi Hire Solutions Ltd | Health & social care | 2021 |
| Medi Simtech Limited | Wholesale & retail | 2021 |
| Medical Simulation Solutions Limited | Information & communication | 2023 |
| Meds Link Global Ltd | Wholesale & retail | 2025 |
| Megajam Consultancy Limited | Professional & scientific | 2012 |
| Melerak Ltd | Construction | 2022 |
| Melior Holdings Nottingham Limited | Financial services | 2014 |
| Melior Land 2013 Limited | Construction | 2013 |
| Melior Land Limited | Construction | 2009 |
| Mellors' Garage Ltd | Wholesale & retail | 2026 |
| Men's Support Limited | Health & social care | 2025 |
| Mercia Garden Products Limited | Manufacturing | 1943 |
| Merkur Gaming UK Limited | Financial services | 2014 |
| Merkur WHS Limited | Financial services | 2026 |
| Mermaid Cove Limited | Arts & recreation | 2018 |
| Meteor IT Limited | Information & communication | 2005 |
| MG (UK Holdings) Limited | Other services | 2019 |
| MGATA24 Care Limited | Health & social care | 2023 |
| MGM Interiors Ltd | Construction | 2018 |
| MHP Holdings Limited | Real estate | 2008 |
| MHS Storage Ltd | Transport & logistics | 2026 |
| MI Drone Ltd | Professional & scientific | 2021 |
| MIA Holdings (Notts) Ltd | Financial services | 2018 |
| Michael Femades Goldsmith and Jewellers Ltd | Manufacturing | 2025 |
| Michael Ramsden PGA Ltd | Wholesale & retail | 2023 |
| Microclouds Ltd | Information & communication | 2025 |
| Middlebank Management Ltd | Real estate | 2010 |
| Middlebeck Care Ltd | Administrative & support | 2023 |
| Middlebeck Gymnastics Club Ltd | Education | 2025 |
| Middleton Stores Limited | Wholesale & retail | 2013 |
| Midland Feeds Holding Limited | Financial services | 2018 |
| Midland Feeds Limited | Manufacturing | 2018 |
| Midland Steel Services Ltd | Construction | 2017 |
| Midlands Cargo Ltd | Transport & logistics | 2025 |
| Midlands Estate Management Co. Limited | Construction | 1985 |
| Midlands Fitness Games Limited | Arts & recreation | 2022 |
| Midlands Heritage Builders Ltd | Construction | 2019 |
| Midlands Pipeline Services Ltd | Manufacturing | 2021 |
| Midnight Motion Pictures Limited | Information & communication | 2019 |
| Migmaai, Inc. | | 2026 |
| Migration Bars Limited | Hospitality | 2024 |
| Mijas Holdings Ltd | Administrative & support | 2019 |
| Mike Pringle Services Ltd | Professional & scientific | 2012 |
| Mikros Consulting Ltd | Information & communication | 2023 |
| Miler Jewellery Ltd | Manufacturing | 2024 |
| Mill Gardens Ltd | Administrative & support | 2014 |
| Mill Hill Farm (Retford) Limited | Agriculture & fishing | 2012 |
| Mill View Wirksworth Management Company Limited | Households | 2025 |
| Miller Family Investments Limited | Professional & scientific | 2022 |
| Millers Mead (Snettisham) Residents Management Company Limited | Households | 2007 |
| Millfield Property Partners Limited | Professional & scientific | 2023 |
| Millgate Estates Limited | Real estate | 2013 |
| Milly&Sissy Ltd | Wholesale & retail | 2019 |