| Maureen Hayes Ltd | Professional & scientific | 2018 |
| Maverick Signs Ltd | Other services | 2018 |
| Mawer Holdings Ltd | Financial services | 2024 |
| MAX Aviation Limited | Manufacturing | 2017 |
| MAX Joseph Bowring Holdings Ltd | Financial services | 2026 |
| MAY Ventures Ltd | Financial services | 2024 |
| Mayberry Developments Limited | Construction | 2016 |
| Mayet and Harrison Ltd | Health & social care | 2010 |
| Mayfair Close (Lincoln) Limited | Real estate | 2008 |
| Mayo (Caistor) Limited | Administrative & support | 2008 |
| Mayo Crane Hire Limited | Administrative & support | 1997 |
| Mayo Electrical Services Limited | Construction | 2019 |
| MAZ Hirota Dudley Ltd | Professional & scientific | 2025 |
| Mazzy Ltd | Other services | 2019 |
| MB & DC Installations Ltd | Construction | 2020 |
| MB Consulting (Barrow) Limited | Information & communication | 2006 |
| MB Gentry Ltd | Other services | 2017 |
| MB Medical Ltd | Health & social care | 2010 |
| MB Motor Trade Limited | Wholesale & retail | 2015 |
| MB Motors Car Engineering Limited | Wholesale & retail | 2019 |
| MBE Clinical Ltd | Health & social care | 2015 |
| Mbmd Limited | Manufacturing | 2017 |
| MBS Systems and Networks Limited | Information & communication | 2008 |
| MC Driving Haulage Ltd | Transport & logistics | 2024 |
| MC Maintenance Services Ltd | Construction | 2023 |
| MC Plumbing & Heating (Lincoln) Limited | Construction | 2018 |
| MC PUB Co (Holding) Limited | Professional & scientific | 2013 |
| MC2 London Ltd | Agriculture & fishing | 1998 |
| MC2 Trading Ltd | Construction | 2016 |
| Mcardle Building Services Ltd | Construction | 2010 |
| Mcdougall Construction Limited | Construction | 2014 |
| Mcdowall Developments Ltd | Real estate | 2022 |
| Mcfadyen Trauma Ltd | Health & social care | 2013 |
| Mcgeown & SON Drilling Services Ltd | Construction | 2025 |
| Mcgovern Assessments Limited | Administrative & support | 2017 |
| Mcintosh Engineering Limited | Professional & scientific | 2016 |
| Mclaren-Sky-Track Limited | Administrative & support | 2025 |
| Mcloughlin Wealth Group Ltd | Real estate | 2026 |
| MCM Construction (Lincs) Ltd | Construction | 2025 |
| Mcnally Cleaning Limited | Administrative & support | 2014 |
| Mcneil and Co Limited | Financial services | 2020 |
| Mcoye Couture Ltd | Professional & scientific | 2025 |
| MD Heating Services Ltd | Construction | 2025 |
| MD Mpire Limited | Financial services | 2022 |
| MDB Security Services Ltd | Administrative & support | 2022 |
| Mdcb Property Ltd | Real estate | 2022 |
| Mdes Contract Services Ltd | Construction | 2018 |
| Mdes Property Solutions Ltd | Construction | 2018 |
| MDG Plumbing & Heating Ltd | Construction | 2011 |
| MDH Developments (Lincoln) Limited | Real estate | 2018 |
| Mdickie Limited | Information & communication | 2017 |
| MDJ Property Services Limited | Real estate | 2020 |
| Mdjj Consultancy & Coaching Ltd | Professional & scientific | 2024 |
| MDK Architects Limited | Professional & scientific | 2012 |
| MDK Fasteners Limited | Manufacturing | 2006 |
| MDM Civil Engineering Limited | Construction | 2016 |
| Mdog Enterprises Limited | Administrative & support | 2024 |
| MDR Groundworks Ltd | Construction | 2021 |
| Meadowbrook Ventures Ltd | Real estate | 2019 |
| Mead’S Marvellous Rodent Nutrition Ltd | Extraterritorial | 2024 |
| MEANING-4-LIFE Ltd. | Professional & scientific | 2020 |
| Meardsall Boarding Kennels Ltd | Other services | 2024 |
| Meardsall Park Limited | Real estate | 2026 |
| Meaterforce Limited | Information & communication | 2025 |
| Mechigen Ltd | Other services | 2024 |
| Mechtronic Design Limited | Professional & scientific | 2014 |
| MED Trading Limited | Wholesale & retail | 2014 |
| Medcircle UK Ltd | Health & social care | 2019 |
| Medevice Limited | Professional & scientific | 2019 |
| Media Archive of Central England Limited | Arts & recreation | 1996 |
| Media in Motion Ltd | Professional & scientific | 2020 |
| Media IT Limited | Information & communication | 2024 |
| Media Lincs Limited | Information & communication | 2010 |
| Medibach Ltd | Health & social care | 2021 |
| Medidoor Ltd | Other services | 2022 |
| Mediphil Healthcare Recruitment Ltd | Administrative & support | 2015 |
| Medophth Ltd | Health & social care | 2026 |
| Medpark Limited | Construction | 1992 |
| Medx Hub Ltd | Professional & scientific | 2022 |
| Meese Haulage Ltd | Transport & logistics | 2021 |
| MEG Heath UK Ltd | Wholesale & retail | 2021 |
| Megacandy Limited | Wholesale & retail | 2012 |
| Megamix Design & Display Ltd | Manufacturing | 2003 |
| Megamix Holdings Limited | Financial services | 2017 |
| Megawatt Advisors Ltd | Professional & scientific | 2025 |
| Megswell Limited | Wholesale & retail | 1957 |
| Meguna Ltd | Professional & scientific | 2022 |
| MEH Associates Limited | Professional & scientific | 2007 |
| Melaco Hair Ltd | Wholesale & retail | 2024 |
| Melakan Catering Ltd | Hospitality | 2025 |
| Melanie Dunn Properties Ltd | Real estate | 2019 |
| Melbourne Jewellery Ltd | Wholesale & retail | 2025 |
| Meli Greek Coffee Shop & Restaurant Ltd | Hospitality | 2025 |
| Melia Inc Ltd | Construction | 2013 |
| Melior Solutions EOT Limited | Financial services | 2023 |
| Melior Solutions Limited | Administrative & support | 2005 |
| Melissa Taylor Design Ltd | Professional & scientific | 2021 |
| Melita Homes Limited | Real estate | 2026 |
| Melladay Construction & Properties Ltd | Construction | 2025 |
| Meller Electrical Limited | Construction | 2017 |