| Mini City Vault Ltd | Wholesale & retail | 2024 |
| Minibus Rentals Ltd | Administrative & support | 2021 |
| Minrex Ltd | Professional & scientific | 2019 |
| Minster Court (Bracebridge Heath) Limited | Health & social care | 1998 |
| Minster Court (Skellingthorpe) Management Company Limited | Real estate | 1990 |
| Minster Fields Management Company Limited | Real estate | 2013 |
| Minster Gardens Management Limited | Households | 2001 |
| Minster Health Ltd | Health & social care | 2024 |
| Minster Mews (Washingborough) Management Company Limited | Households | 1990 |
| Mint Lane CIC | Wholesale & retail | 2017 |
| Mintem Group Limited | Financial services | 2024 |
| Mintem Holdings Limited | Financial services | 2012 |
| Mintem Limited | Financial services | 2019 |
| Minterly Limited | Information & communication | 2016 |
| Minting (Lincoln) Limited | Construction | 2025 |
| Minty AI Limited | Information & communication | 2025 |
| Minutia Holdings Limited | Professional & scientific | 2021 |
| Miracle & Wonder Limited | Hospitality | 2015 |
| Miracle Span Limited | Professional & scientific | 1974 |
| Miracleman Limited | Construction | 2016 |
| Mirlo Holdings Limited | Financial services | 2024 |
| Mirlo Properties Ltd | Real estate | 2023 |
| MIS Factory Limited | Information & communication | 2008 |
| Miscanthus Growers Limited | Agriculture & fishing | 2010 |
| Miskovic Medical Ltd | Health & social care | 2019 |
| Mission Resourcing Ltd | Administrative & support | 2021 |
| Mist Group Ltd | Financial services | 2025 |
| Mist Property Limited | Real estate | 2018 |
| Mist Services Ltd | Education | 2008 |
| Mitch Ashworth Ltd | Construction | 2020 |
| Mitev & SON Ltd | Wholesale & retail | 2025 |
| MIX Global Ltd | Arts & recreation | 2025 |
| Mixor Food Ltd | Hospitality | 2024 |
| Mizpah UK Limited | Professional & scientific | 2004 |
| MJ Courtmarkers Limited | Construction | 2006 |
| MJ Properties Lincoln Limited | Real estate | 2018 |
| MJB Metalwork Ltd. | Manufacturing | 2019 |
| MJC Electronics Ltd | Manufacturing | 2013 |
| Mjlc Group Limited | Extraterritorial | 2016 |
| Mjlc Ltd | Extraterritorial | 2016 |
| Mjlc Security Services Ltd | Extraterritorial | 2005 |
| MJM Bookkeeping Services Ltd | Other services | 2016 |
| MJM Group Ltd | Construction | 2018 |
| MJM Plumbing (Lincoln) Ltd | Construction | 2015 |
| MJO Property Estates Ltd | Real estate | 2017 |
| MJS Housing Ltd | Real estate | 2024 |
| MJT Site Engineering Ltd | Professional & scientific | 2020 |
| MK & Sons Homes Ltd | Construction | 2020 |
| MK Alliance Ltd | Wholesale & retail | 2026 |
| MK Bargain Ltd | Wholesale & retail | 2016 |
| MK Electrical (Lincoln) Limited | Construction | 2020 |
| MK Freight Ltd | Transport & logistics | 2022 |
| Mkca LLP | | 2016 |
| MKD Haulage Ltd | Transport & logistics | 2025 |
| MKS Catering Limited | Hospitality | 2026 |
| Mkwandas Care Ltd | Health & social care | 2016 |
| Mlsk Limited | Real estate | 2019 |
| MLW Contractors Ltd | Construction | 2021 |
| MM Haulage Ltd | Transport & logistics | 2019 |
| MM247 Limited | Real estate | 2018 |
| Mmclothing Ltd | Wholesale & retail | 2025 |
| MMX Global Limited | Professional & scientific | 2016 |
| MNM Global Solutions Limited | Professional & scientific | 2025 |
| MNP Renovation Ltd | Construction | 2023 |
| MO Landscapers Ltd | Administrative & support | 2024 |
| Mobfix Limited | Wholesale & retail | 2023 |
| Mobile Camper Care Ltd | Other services | 2022 |
| Mobile Zone (Lincoln) Ltd | Wholesale & retail | 2022 |
| MOBILETYREMAN247 Ltd | Wholesale & retail | 2025 |
| Mocka Properties Ltd | Real estate | 2021 |
| Mode Physiotherapy Ltd | Health & social care | 2022 |
| Mode Trans Limited | Transport & logistics | 2019 |
| Modern Biomedical Solutions Limited | Health & social care | 2025 |
| Modern Heritage Styling Limited | Other services | 2019 |
| Modern&Professional Ltd | Wholesale & retail | 2026 |
| Modubuild Limited | Construction | 2015 |
| Modulinc Ltd | Information & communication | 2025 |
| Mokum 020 Ltd | Wholesale & retail | 2024 |
| Molly & ME Interiors Ltd | Wholesale & retail | 2018 |
| Momma D’S Cleans Limited | Administrative & support | 2025 |
| Monarch Asset Finance Limited | Financial services | 2022 |
| Monarch Enterprises Limited | Other services | 2014 |
| Monarch Leisure Limited | Arts & recreation | 2016 |
| Moneties Limited | Administrative & support | 2024 |
| Monkebuddhi Ltd | Information & communication | 2025 |
| MONKEY38 Limited | Transport & logistics | 2014 |
| Monks Road Decor Ltd | Construction | 2026 |
| Monsal Head Holdings Ltd | Financial services | 2023 |
| Monson Corner Management Limited | Households | 2004 |
| Monson Fish Bar Ltd | Hospitality | 2022 |
| Monson Mews Management Company Limited | Households | 2007 |
| Monson Motor Factors Ltd | Wholesale & retail | 2014 |
| Mont & Mont Limited | Education | 2025 |
| Montane Group Limited | Administrative & support | 2020 |
| Montgo Consultancy Ltd | Real estate | 2020 |
| Montgomery Retail Group Ltd | Wholesale & retail | 2026 |
| Monument JCH (Trustees) Limited | Financial services | 2025 |
| Monumental Homes Limited | Construction | 2019 |
| Monza Group International Ltd | Professional & scientific | 2026 |
| Moon Civils Limited | Construction | 2016 |