| Magenta Cars Ltd | Wholesale & retail | 2024 |
| Magenta Photographic Studios Limited | Professional & scientific | 2006 |
| Maghtufssons Ltd | Wholesale & retail | 2024 |
| Magic Box Face Paints Limited | Wholesale & retail | 2022 |
| Magic Chef Takeaway Ltd | Hospitality | 2021 |
| Magic Flame Takeway Limited | Hospitality | 2026 |
| Magic Smile Co Limited | Manufacturing | 2018 |
| Magical Mystery Tour (NE) Ltd | Wholesale & retail | 2020 |
| Magnet and Steel Properties Ltd | Real estate | 2022 |
| Magnet Motor Company Ltd | Wholesale & retail | 2025 |
| Magnetic Mortgage Solutions Limited | Financial services | 2023 |
| Magnetic North Productions Ltd | Information & communication | 2025 |
| Magnetic Seven Limited | Real estate | 2016 |
| Magnitude Ventures Ltd | Wholesale & retail | 2021 |
| Magnus and Wolf Limited | Administrative & support | 2023 |
| Magpie Building Services Ltd | Construction | 2022 |
| Magpie Maids Ltd | Administrative & support | 2025 |
| Magpie Solar Ltd | Construction | 2025 |
| Magpie Tests Ltd | Professional & scientific | 2019 |
| Magpiestays Ltd | Hospitality | 2025 |
| Magpye Ltd | Manufacturing | 2018 |
| Magtoto Logistics Ltd | Transport & logistics | 2025 |
| Maguires Barbershop Limited | Wholesale & retail | 2009 |
| MAH Distribution Ltd | Wholesale & retail | 2023 |
| Mahak London Ltd | Wholesale & retail | 2025 |
| Mahar Sons Ltd | Wholesale & retail | 2026 |
| Mahas Locums Ltd | Health & social care | 2022 |
| Mahavir Group Ltd | Hospitality | 2023 |
| Mahawar Bariatrics Limited | Health & social care | 2021 |
| Mahi PVT Ltd | Wholesale & retail | 2023 |
| Mahiseller Limited | Wholesale & retail | 2022 |
| Mahmood and Ashraf Property Services Limited | Real estate | 2018 |
| Mahmood Brothers Limited | Real estate | 2012 |
| Maia Property NE Ltd | Real estate | 2024 |
| Mail 2 U Ltd | Other services | 2022 |
| Maine Industrial & Automotive Ltd | Professional & scientific | 2014 |
| Maine One Limited | Energy | 2025 |
| Maine Properties Ltd | Real estate | 2024 |
| Mainline Advertising (UK) Limited | Wholesale & retail | 2000 |
| Mains Place (Management) Limited | Administrative & support | 1998 |
| Mainstreet International Limited | Administrative & support | 2020 |
| Mainstreet Publishing Limited | Information & communication | 2011 |
| Mainstreet Rental Services Limited | Extraterritorial | 1994 |
| Mainwood Properties Ltd | Real estate | 2001 |
| Maison Verdan Limited | Professional & scientific | 2025 |
| MAJ Installations Ltd | Construction | 2024 |
| Majedamiah Limited | Administrative & support | 2022 |
| Majestic North East Cleaners Ltd | Administrative & support | 2025 |
| Majid Retail Ltd | Wholesale & retail | 2024 |
| Majo Locum Ltd | Health & social care | 2025 |
| Major Family Law Limited | Professional & scientific | 2009 |
| MAK Lettings Ltd | Real estate | 2017 |
| MAK Property Development Ltd | Hospitality | 2014 |
| Makaan AUR Zameen Ltd | Real estate | 2026 |
| Makain Merchant Ltd | Wholesale & retail | 2023 |
| Make IT POP Ltd | Manufacturing | 2017 |
| Make Your Habits Ltd | Other services | 2022 |
| Make Your Way North East Community Interest Company | Health & social care | 2023 |
| Makemagic Ltd | Information & communication | 2025 |
| Making Room (Collective) CIC | Professional & scientific | 2026 |
| Making Room (Projects) Ltd | Professional & scientific | 2024 |
| Making Strydes Community CIC | Administrative & support | 2026 |
| Making Strydes Limited | Professional & scientific | 2022 |
| Mako Bespoke Ltd | Manufacturing | 2022 |
| Malaika Pets Limited | Wholesale & retail | 2025 |
| Malange Limited | Administrative & support | 2005 |
| Malcolm Court Management (Monkseaton) Limited | Households | 1991 |
| Malcolm Morris Limited | Water & waste | 2026 |
| Malcolm N Scott Ltd | Construction | 2019 |
| Malcolm Services Limited | Other services | 2019 |
| Male Luxe Aesthetics Ltd | Other services | 2022 |
| Maleti Wash & Co Ltd | Wholesale & retail | 2020 |
| Malhotra & Co. Limited | Wholesale & retail | 1974 |
| Malhotra 101 Limited | Real estate | 2025 |
| Malhotra Addison Limited | Real estate | 2019 |
| Malhotra Care Homes (Sunderland) Limited | Health & social care | 2013 |
| Malhotra Care Homes Limited | Health & social care | 2009 |
| Malhotra Commercial Property Limited | Real estate | 1991 |
| Malhotra Family Holdings Limited | Professional & scientific | 2012 |
| Malhotra FIN (UK) Limited | Financial services | 2022 |
| Malhotra Group PLC | Extraterritorial | 2026 |
| Malhotra Leisure Limited | Hospitality | 2009 |
| Malhotra Property Developments Limited | Construction | 2018 |
| Malhotra Property Investments Limited | Real estate | 2000 |
| Malhotra Property Limited | Hospitality | 1990 |
| Malik Abdul Ltd | Real estate | 2026 |
| Malik Property Group Ltd | Real estate | 2019 |
| Malik Siddique Ltd | Health & social care | 2010 |
| Malikss Logistics UK Ltd | Transport & logistics | 2025 |
| Malin and Forth Limited | Real estate | 2025 |
| Maling Limited | Professional & scientific | 2018 |
| Maling Street Management Company Limited | Real estate | 2014 |
| Mallett Prime Holdings Ltd | Real estate | 2024 |
| Malleum U.K. Limited | Information & communication | 2024 |
| Malo-Idm Ltd. | Information & communication | 2002 |
| Malone Property (North) Limited | Real estate | 2024 |
| Maltings Pictures Ltd | Information & communication | 2022 |
| Mama Roti Limited | Hospitality | 2023 |
| Mammoth Cable Solutions UK Ltd | Information & communication | 2025 |
| Mammoth Cabling Group Ltd | Construction | 2026 |