| Little Minnows Ltd | Health & social care | 2020 |
| Little Moves Ltd | Transport & logistics | 2024 |
| Little Wonders ST Austell Limited | Wholesale & retail | 2025 |
| Live Wire Electric Limited | Construction | 2009 |
| LKN Group Ltd | Other services | 2025 |
| LKT Transport Ltd | Transport & logistics | 2024 |
| Llawnroc Furniture Cornwall Ltd | Manufacturing | 2017 |
| Lmpg Ltd | Manufacturing | 2023 |
| LOC Building and Electrical Ltd | Construction | 2024 |
| Local Interactive Services Online Limited | Information & communication | 1999 |
| Loop Works Holdings Limited | Information & communication | 2023 |
| Lottie Lewis Ltd | Information & communication | 2018 |
| Lovering House Management Company Limited | Households | 2008 |
| Lowe Accounting Solutions Limited | Professional & scientific | 2022 |
| Lower Cargwyn Management Company Ltd | Households | 2019 |
| LU - NEG Group Ltd | Wholesale & retail | 2021 |
| Lucky Boat Commerce Ltd | Real estate | 2021 |
| Lucy Nicholas Ltd | Hospitality | 2023 |
| Lumiere Media Ltd | Professional & scientific | 2024 |
| Lumin Consultancy Ltd | Professional & scientific | 2025 |
| Lusso Amore Limited | Wholesale & retail | 2026 |
| Luxdens Ltd | Health & social care | 2019 |
| Luxhomeuk Ltd | Real estate | 2024 |
| Luxskn Limited | Other services | 2025 |
| Lyfelights Limited | Wholesale & retail | 2023 |
| Lynn's Inns Ltd | Hospitality | 2018 |
| M&D Developments (Cornwall) Ltd | Construction | 2006 |
| M.A.R. Roofing Services Limited | Construction | 2003 |
| M.Ramsay Ltd | Health & social care | 2022 |
| MA Hitchens Holdings Limited | Financial services | 2024 |
| MAD Hatter Sports Events Ltd | Arts & recreation | 2017 |
| Madison Enterprises (Global) LLP | | 2024 |
| Mahogany Property Limited | Real estate | 2024 |
| Maker and Rame Limited | Professional & scientific | 2025 |
| Making Skills Limited | Education | 2026 |
| Mal-Vw Limited | Wholesale & retail | 2011 |
| Malcolm Harris Plumbing and Heating Limited | Construction | 2017 |
| Malcolm Harris Projects Limited | Construction | 2017 |
| Mallard Connect Ltd | Wholesale & retail | 2014 |
| Manage HR Ltd | Administrative & support | 2021 |
| Manfoon Cuisine Limited | Hospitality | 2022 |
| Manfoon Dinner Limited | Hospitality | 2025 |
| Manor Made Cornwall Ltd | Hospitality | 2021 |
| Mansell Commercial Services Limited | Wholesale & retail | 1982 |
| Marie Morrison Designs Limited | Wholesale & retail | 2013 |
| Mark of Human Origin Ltd | Other services | 2026 |
| Marley Developments S.W Ltd | Construction | 2020 |
| Martin Gaylard Speciality Cheese Ltd | Manufacturing | 2020 |
| Martins Bakery (Cornwall) Limited | Manufacturing | 2007 |
| Masala and Masala Ltd | Hospitality | 2026 |
| Mashfashion Ltd | Wholesale & retail | 2015 |
| Master Blaster (South West) Limited | Administrative & support | 2022 |
| Matt Jago Plumbing and Heating Ltd | Construction | 2019 |
| Matthews Bros. Limited | Agriculture & fishing | 2010 |
| Maverick Construction Cornwall Limited | Construction | 2026 |
| Mays Cornwall Limited | Financial services | 2022 |
| MC Metrix Ltd | Professional & scientific | 2025 |
| Mccartney Holdings Ltd | Financial services | 2025 |
| MCG Electrical South West Limited | Construction | 2023 |
| MCH Wheal Northey Ltd | Health & social care | 2024 |
| MCV Vehicle Storage Limited | Transport & logistics | 2018 |
| MD Sales Southwest Ltd | Professional & scientific | 2021 |
| Megan White Wealth Management Ltd | Financial services | 2024 |
| Meshed Web Limited | Information & communication | 2019 |
| Meva Quick Taxi Service Limited | Transport & logistics | 2024 |
| Mews Management Company (Charlestown) Limited | Households | 2021 |
| Michael and Dawn Powell Limited | Real estate | 1964 |
| MID Cornwall Construction & Landscaping Ltd. | Construction | 2011 |
| MID Cornwall Fabrications Ltd | Manufacturing | 2022 |
| MID Cornwall Hub Ltd | Health & social care | 2011 |
| MID Cornwall MOT Centre Ltd | Wholesale & retail | 2019 |
| MID Cornwall Valeting Limited | Wholesale & retail | 2016 |
| Midax Engineering Limited | Manufacturing | 1975 |
| Mill House Properties (Cornwall) Limited | Real estate | 2015 |
| Mills Engines & Driver Ltd | Manufacturing | 2026 |
| Mimi's Vintage Diner Limited | Hospitality | 2012 |
| Mister Modular Limited | Professional & scientific | 2018 |
| Mitchell's Boatyard Ltd | Transport & logistics | 2025 |
| Mitingu Limited | Administrative & support | 2014 |
| Mjbgarmz Limited | Wholesale & retail | 2021 |
| MJS Cluck & Chuck Ltd | Hospitality | 2023 |
| MJS JAM & Dodger Ltd | Real estate | 2023 |
| MK Window and Door Repairs Ltd | Construction | 2022 |
| MM Club Mart Ltd | Wholesale & retail | 2025 |
| Mogulme Developments Ltd | Construction | 2022 |
| Molyneaux Builders Limited | Construction | 2018 |
| Moon Rune Games Ltd | Information & communication | 2024 |
| Morgen Media Walls & Fires Ltd | Manufacturing | 2021 |
| Mortgage Pensions & Investments LLP | | 2006 |
| Mortgage Works Limited | Financial services | 2013 |
| Mount Stamper Farm Ltd | Agriculture & fishing | 2024 |
| MPS Southwest Ltd | Wholesale & retail | 2018 |
| Muse Collective Ltd | Other services | 2026 |
| Music Docs UK Ltd | Information & communication | 2025 |
| N Richards & Sons Ltd | Professional & scientific | 1987 |
| Nansladron Apartments Management Limited | Real estate | 2014 |
| Natural Nursery Resources Ltd | Wholesale & retail | 2016 |
| Nature's Holistic Solutions Ltd | Wholesale & retail | 2022 |
| ND (Plymouth) Limited | Professional & scientific | 2019 |
| Neighbours of North Street Limited | Extraterritorial | 2016 |