| Lucas MAE Ltd | Real estate | 2023 |
| Lucky Orbit Ltd | Arts & recreation | 2026 |
| Lucus Vans Ltd | Wholesale & retail | 2024 |
| Luisa Delfi Media Ltd | Professional & scientific | 2025 |
| Lula Beach Club Ltd | Hospitality | 2026 |
| Luxon Lettings Ltd | Real estate | 2024 |
| Luxulyan House Management Company Limited | Construction | 1997 |
| LW Cafe Limited | Hospitality | 2023 |
| LYS Noweth Management Company Limited | Households | 2013 |
| Lzgovenek Limited | Agriculture & fishing | 2013 |
| LZT Consolidated Limited | Financial services | 2022 |
| M Yates and Sons Limited | Manufacturing | 1999 |
| MAC Technologies Limited | Wholesale & retail | 2014 |
| Macca's Pool Tiling Services Ltd | Construction | 2024 |
| Macintyre Technology Consulting Ltd | Information & communication | 2025 |
| Macmanlee Limited | Other services | 2019 |
| Macro Health Limited | Professional & scientific | 2025 |
| Made by Murphy Fitness Ltd | Health & social care | 2024 |
| Made for Life Limited | Wholesale & retail | 2007 |
| Made for Life Organics Limited | Extraterritorial | 2007 |
| Madiba Surf Limited | Wholesale & retail | 2011 |
| Maen Karne Aggregates Limited | Water & waste | 2005 |
| Maen Karne Concrete Products Ltd | Wholesale & retail | 2010 |
| Maharajah Newquay Ltd | Hospitality | 2025 |
| Maida Vale Properties Limited | Real estate | 2009 |
| Makai Coliving Limited | Real estate | 2023 |
| Makc Ltd | Wholesale & retail | 2026 |
| Mallon Properties Ltd | Real estate | 2026 |
| Management Solutions and Consulting Limited | Professional & scientific | 2007 |
| Manaton Meadows Ltd | Agriculture & fishing | 2026 |
| Manders Realty Ltd | Real estate | 2024 |
| Manta Power Ltd | Construction | 2021 |
| Manuxcript Ltd | Information & communication | 2024 |
| Marc Trading Apparel Ltd | Wholesale & retail | 2025 |
| Marcus Hill Management Limited | Households | 2026 |
| Maria Richards Conveyancing Services Limited | Professional & scientific | 2022 |
| Marianne Bradshaw Ltd | Professional & scientific | 2025 |
| Marie Mills (Art) Limited | Arts & recreation | 2008 |
| Marine Services and Coaching Limited | Manufacturing | 2014 |
| Mark Brewer Engineering Ltd | Professional & scientific | 2013 |
| Mark Evans Car Sales Ltd | Wholesale & retail | 2025 |
| Mark Rickarby Hire Limited | Construction | 2015 |
| Markus Digital Content Ltd | Information & communication | 2018 |
| Marshlettes Property Ltd | Real estate | 2022 |
| Marston Partnership LLP | | 2022 |
| Marwick Marketing Ltd | Professional & scientific | 2020 |
| MAS Build SW Ltd | Construction | 2026 |
| Mashariki Africa Exports Ltd | Administrative & support | 2025 |
| Matt Parkin Resources Ltd | Manufacturing | 2018 |
| Matt Prior Limited | Construction | 2013 |
| Mattch Box Ltd | Professional & scientific | 2019 |
| Maverix Supply Co Ltd | Wholesale & retail | 2023 |
| Mawgan Pads Ltd | Hospitality | 2021 |
| Maximum Effort Ltd | Wholesale & retail | 2026 |
| Mccardell and Thompson Ltd | Agriculture & fishing | 2018 |
| Meadow Court (Falmouth) Management Company Limited | Households | 2008 |
| Medi Logistics International Limited | Wholesale & retail | 2022 |
| Medistaff Connect Ltd | Information & communication | 2025 |
| Menalhyl Farm Ltd | Agriculture & fishing | 2025 |
| Mendes Properties Limited | Real estate | 2016 |
| MEP South West Ltd | Construction | 2022 |
| Mercury Retro Limited | Real estate | 2025 |
| Mermaid Court Management Company (Newquay) Limited | Real estate | 2000 |
| Merriman Mineral Processing LLP | | 2005 |
| Metaspeech Ltd | Other services | 2014 |
| Methanexchange Ltd | Agriculture & fishing | 2025 |
| Metronome Distribution Limited | Information & communication | 2002 |
| Metronome Recordings Limited | Manufacturing | 1992 |
| Mexzim Ltd | Hospitality | 2023 |
| Meysam Ltd | Hospitality | 2023 |
| Michael Laffoley Limited | Construction | 2002 |
| Micro D.I.Y. Trade Centre Limited | Wholesale & retail | 1979 |
| Middletown Developments Ltd | Real estate | 2017 |
| Miju Holdings Limited | Financial services | 2024 |
| Miju Salisbury Ltd | Real estate | 2024 |
| Mike Martin Refrigeration Limited | Professional & scientific | 2021 |
| Mike Winfield & Sons Construction Limited | Wholesale & retail | 2006 |
| Miller Leadership Consulting Limited | Professional & scientific | 2025 |
| Minerva Guest House Ltd | Hospitality | 2022 |
| Mircurius Limited | Wholesale & retail | 2011 |
| Mitchell Garden & Cafe Ltd | Agriculture & fishing | 2023 |
| Mitchell Metal Fabrication Limited | Manufacturing | 2023 |
| Mitchell Residential Management Company Limited | Extraterritorial | 2007 |
| Mitime Limited | Hospitality | 2021 |
| MIX Group Limited | Hospitality | 2021 |
| MJB Solutions SW Ltd | Administrative & support | 2012 |
| MJD Accountancy Services Ltd | Professional & scientific | 2023 |
| MK Port and Maritime Advice Limited | Transport & logistics | 2023 |
| MKB IT Systems Ltd | Information & communication | 2018 |
| Mo's Restaurant NQY Limited | Hospitality | 2019 |
| Modo MIO Group Ltd | Real estate | 2024 |
| Modular Worlds Ltd | Manufacturing | 2020 |
| Modular Worlds Miniatures Ltd | Manufacturing | 2025 |
| Mogit Consultancy Limited | Information & communication | 2020 |
| Mojo Construction (Cornwall) Limited | Construction | 2023 |
| Mojo Cosmetics Ltd | Other services | 2026 |
| Mojo International Limited | Manufacturing | 2022 |
| Monday Club Ltd | Real estate | 2023 |
| Money CAN BE FUN Limited | Financial services | 2003 |
| Monoluxe Limited | Manufacturing | 2012 |