| Mcguire & Sons Builders Ltd | Construction | 2011 |
| Mchale Solutions Limited | Professional & scientific | 2005 |
| Mdgcdevelopments Ltd | Construction | 2023 |
| Meatery Group Ltd | Wholesale & retail | 2021 |
| MED Learn Training Limited | Other services | 2012 |
| MED Motors Ltd | Wholesale & retail | 2012 |
| Medway Consult Limited | Professional & scientific | 2023 |
| Meep Meep Creative Limited | Professional & scientific | 2009 |
| Mega IAL Electronica UK Ltd | Wholesale & retail | 2024 |
| Melville Apartments Management Company Ltd | Real estate | 2010 |
| Memorabilia UK Limited | Wholesale & retail | 2013 |
| Mercury Conveyor Systems Ltd | Wholesale & retail | 2021 |
| Merrick & Co Property Limited | Real estate | 2021 |
| Merrick & Day Limited | Manufacturing | 2001 |
| MES Amies Ltd | Other services | 2024 |
| Mexiton Ltd | Households | 2002 |
| MG Sales & Consultancy Limited | Wholesale & retail | 2009 |
| Mg&J Holdings Ltd | Administrative & support | 2025 |
| MI Electricians Ltd | Manufacturing | 2025 |
| MI Group Ltd | Financial services | 2025 |
| MI Plumbing & Heating Ltd | Construction | 2025 |
| Michael Fitzgerald Ltd | Financial services | 2021 |
| Michael Herrington Racing Ltd | Other services | 2004 |
| Michaels Hairdressers Limited | Other services | 2017 |
| MID Lincs Air Ltd | Manufacturing | 2026 |
| Middlefield Farming Limited | Financial services | 2025 |
| Mide Enterprises Limited | Hospitality | 2024 |
| Midland Packaging Dies Ltd | Professional & scientific | 2012 |
| Mike Jones Building Services Ltd | Construction | 2024 |
| Miles Maintenance Ltd | Manufacturing | 2016 |
| Milles Charitable Foundation Limited | Other services | 2009 |
| Millhaven Canine Rehabilitation Limited | Professional & scientific | 2016 |
| MJC Advisory Limited | Professional & scientific | 2022 |
| MJJ Electrical Contractors Ltd | Construction | 2026 |
| MK Properties Lincs Limited | Real estate | 2025 |
| MKS Groundcare Ltd | Administrative & support | 2017 |
| MMC Social Limited | Information & communication | 2020 |
| MMP Services Limited | Professional & scientific | 2020 |
| MMW Property Limited | Real estate | 2026 |
| Mngr Limited | Information & communication | 2025 |
| Modular Roofing Blankets Limited | Manufacturing | 2025 |
| MOG Estates Ltd | Real estate | 2023 |
| Monkey Biscuit Ltd | Wholesale & retail | 2017 |
| Morden Road Ltd | Real estate | 2025 |
| Morse Business Finance Limited | Financial services | 2008 |
| Mosporium Ltd | Transport & logistics | 2025 |
| Mouldmakers Limited | Manufacturing | 2014 |
| Moulton Finance Ltd | Financial services | 2021 |
| MP Transline Ltd | Transport & logistics | 2019 |
| MPB Bioproducts Limited | Agriculture & fishing | 2007 |
| MPS Aviation Limited | Administrative & support | 2008 |
| MPS Care Group Limited | Professional & scientific | 2013 |
| MPS Care Limited | Professional & scientific | 2006 |
| MPS Northfields Limited | Construction | 2012 |
| MR JIG Ltd | Professional & scientific | 2022 |
| MRB Holdings (Kirton Lindsey) Ltd | Financial services | 2024 |
| MRK Electric Services Ltd | Construction | 2012 |
| MRS Q'S Private Tuition & Careers Ltd | Education | 2024 |
| MS Supercars Limited | Wholesale & retail | 2015 |
| MSK Property Developers Ltd | Real estate | 2025 |
| MT Estates Limited | Real estate | 2014 |
| Mullins Security Consultancy Limited | Administrative & support | 2015 |
| Munster & Morston Limited | Wholesale & retail | 2024 |
| MVR Mechanical Limited | Professional & scientific | 2023 |
| Mxnn Ltd | Wholesale & retail | 2025 |
| My Business Genie Ltd | Information & communication | 2020 |
| My Home Developments Ltd | Construction | 2021 |
| Myers Dudley-Gritt Limited | Professional & scientific | 2021 |
| Mynah Bird IT Limited | Information & communication | 2012 |
| N J F Holdings Ltd | Financial services | 2023 |
| N Loates & SON Limited | Agriculture & fishing | 2017 |
| N Noble Landscaping and Construction Ltd | Construction | 2021 |
| N Proctor Plumbing and Heating Limited | Construction | 2016 |
| N. Hallsworth Limited | Professional & scientific | 2019 |
| N3WLIFE Developments Ltd | Real estate | 2025 |
| Nandco Ltd | Construction | 2020 |
| Narkis Risk Ltd | Administrative & support | 2024 |
| Natalie Lucy Ltd | Transport & logistics | 2024 |
| National Academy of Foot Health Education Ltd | Education | 2023 |
| Navenby Travel Limited | Administrative & support | 2012 |
| Navi & M Ltd | Hospitality | 2026 |
| NB Property Developments Limited | Construction | 2008 |
| Neil Hepworth Limited | Other services | 2016 |
| Nellyukstore Ltd | Wholesale & retail | 2026 |
| Nest Homes & Developments Ltd | Construction | 2021 |
| Neth Solutions Ltd | Administrative & support | 2025 |
| Neville Barnes Limited | Manufacturing | 1981 |
| Neville Fickling Limited | Arts & recreation | 1998 |
| New Design Furniture Limited | Wholesale & retail | 1991 |
| New Design Group Limited | Manufacturing | 1959 |
| New Design Group Property Limited | Real estate | 2024 |
| New Florentinos Ltd | Hospitality | 2025 |
| New ME by JB Ltd | Wholesale & retail | 2021 |
| New Park Quarry Ltd | Mining & quarrying | 2022 |
| Newt Manor Ltd | Administrative & support | 2025 |
| Nexgencars Ltd | Wholesale & retail | 2026 |
| Nexus Chafer Ltd. | Manufacturing | 2024 |
| Nexus Cleaning Services Ltd | Administrative & support | 2026 |
| NFE Commercials Ltd | Wholesale & retail | 2025 |
| NGS Developments Limited | Professional & scientific | 2009 |