| Liam Blayney Carpenters Ltd | Manufacturing | 2020 |
| Liberty Carpets Limited | Wholesale & retail | 2005 |
| Links Electrical Supplies Ltd | Wholesale & retail | 2000 |
| Lions Kebab House Ltd | Hospitality | 2024 |
| Littlemill Media Limited | Information & communication | 2000 |
| Living Here Ltd | Real estate | 2015 |
| LJV Construction Ltd. | Construction | 2012 |
| Llabwst Farm Ltd | Hospitality | 2021 |
| Llaithddu Eggs Limited | Agriculture & fishing | 2012 |
| Llandinam Community Interest Company | Other services | 2024 |
| Llawerch Productions Ltd | Wholesale & retail | 2025 |
| Llys Y Brenin (Property Management) Limited | Households | 1994 |
| Loading Services Ltd | Wholesale & retail | 2017 |
| Local Spice Ltd | Hospitality | 2018 |
| Logas International Risk Management and Consultancy Ltd | Administrative & support | 2012 |
| Longman Project Developments Limited | Construction | 2017 |
| Loqui AV Ltd | Manufacturing | 2024 |
| Lovatt Bros Properties Limited | Real estate | 2007 |
| Lower Fishpools Lodges Ltd | Real estate | 2023 |
| Luca Limited | Construction | 2019 |
| Lucham Connection Ltd | Professional & scientific | 2023 |
| Lucky Hormony Ltd | Hospitality | 2025 |
| M Bowen Building Ltd | Construction | 2019 |
| M Bufton Plumbing & Heating Services Limited | Construction | 2003 |
| M.B.S Protection Services Limited | Administrative & support | 2015 |
| M.Howard Ltd | Administrative & support | 2019 |
| Machina Systems Ltd | Information & communication | 2025 |
| Magnolia Homes PVT Limited | Real estate | 2023 |
| Maguinness Limited | Manufacturing | 2025 |
| Maison AAE Limited | Manufacturing | 2025 |
| MAK Risk Management Solutions Ltd | Administrative & support | 2014 |
| Maldwyn Dragons Gymnastic Club Limited | Arts & recreation | 2013 |
| Maldwyn Nursery & Family Centre | Education | 1991 |
| Malpaso Productions Limited | Administrative & support | 2023 |
| Mango 5 Limited | Administrative & support | 2021 |
| Manor Farm Lodges Limited | Hospitality | 2017 |
| Marc a Davies Limited | Wholesale & retail | 2022 |
| Margot Faraci Ltd | Professional & scientific | 2026 |
| Marley Eggs Limited | Professional & scientific | 2016 |
| Marshnet Ltd | Information & communication | 2024 |
| Masarn Ltd. | Information & communication | 2024 |
| Matrix Stone Limited | Construction | 2006 |
| Matthew Thomas Insurance Brokers Ltd | Financial services | 2022 |
| MC Conversions Ltd | Construction | 2022 |
| Meddins Farming Limited | Agriculture & fishing | 2025 |
| Melrose Bros Ltd | Agriculture & fishing | 2020 |
| Melusi Services Ltd | Hospitality | 2018 |
| MEN Shed Newtown C.I.C. | Health & social care | 2023 |
| MG Brush Holdings Limited | Financial services | 2022 |
| MGH Bowen Ltd | Professional & scientific | 2014 |
| MID Wales Food and Land Trust Limited | Administrative & support | 2004 |
| MID Wales LOG Burners and Flues Limited | Other services | 2015 |
| MID Wales Manufacturing Group Limited | Other services | 1994 |
| MID Wales Plumbing and Heating Supplies Limited | Wholesale & retail | 2014 |
| MID Wales Property Ltd. | Construction | 1998 |
| MID Wales Windows & Conservatories Ltd | Construction | 2013 |
| Mid-Wales Vintage Machinery Club Limited | Other services | 1984 |
| Midland OIL Engine Club Limited | Other services | 1984 |
| Mile Solutions Ltd | Construction | 2024 |
| Millbrook Mouldings Limited | Manufacturing | 2010 |
| Millroom Mixing Machines Limited | Manufacturing | 1954 |
| Milner Exports (Fine Foods) Limited | Wholesale & retail | 1972 |
| Milwyn Jenkins Limited | Professional & scientific | 2008 |
| Minerva Garage Limited | Wholesale & retail | 2026 |
| Minoka Properties Ltd | Construction | 2024 |
| Mobile Enterprise Developments Limited | Manufacturing | 2018 |
| Mondrix Estates Limited | Real estate | 2025 |
| Montgomery Vineyard Limited | Manufacturing | 2014 |
| Montgomeryshire Community Regeneration Association Cymdeithas Adfywio Cymunedol Maldwyn | Health & social care | 1950 |
| Montgomeryshire Family Crisis Centre | Hospitality | 2008 |
| Montgomeryshire Vintage Club Limited | Other services | 2015 |
| Monty & Mabel Creative Limited | Wholesale & retail | 2018 |
| Morgan Griffiths Limited Liability Partnership | | 2007 |
| Morreco Holdings Limited | Financial services | 2024 |
| MOS Kebab Ltd | Hospitality | 2024 |
| Motor Control Warehouse Limited | Wholesale & retail | 2012 |
| Mount Longford Developments Ltd | Real estate | 2008 |
| Mozz Cycling 2008 Limited | Wholesale & retail | 2007 |
| Mozz Cycling Limited | Wholesale & retail | 2006 |
| Mrjs Security Ltd | Administrative & support | 2019 |
| MSC Quantity Surveying Limited | Professional & scientific | 2025 |
| MSR Rural Business Consultancy Limited | Professional & scientific | 2013 |
| MTJ Construction Consulting Limited | Professional & scientific | 2021 |
| Mwmx Events Limited | Arts & recreation | 2025 |
| My Choice Trading Ltd | Wholesale & retail | 2025 |
| N S Davis Limited | Financial services | 2021 |
| Nantyrhafod Limited | Agriculture & fishing | 2019 |
| Natoura Voyage Ltd | Administrative & support | 2014 |
| NEO Fabrication and Erection Limited | Manufacturing | 1988 |
| NEO RIA Ltd | Wholesale & retail | 2023 |
| Netfirst Limited | Professional & scientific | 1996 |
| Neuadd Llwyd Farm Limited | Agriculture & fishing | 2021 |
| Neville Commercial Properties Limited | Real estate | 2026 |
| New Direction Energy & Financial Ltd | Financial services | 2018 |
| New Home Furnishings Limited | Manufacturing | 2014 |
| Newton K Valeting Ltd | Administrative & support | 2025 |
| Newtown & District Automobile Club Limited | Arts & recreation | 1979 |
| Newtown Brothers Barber Ltd | Other services | 2022 |
| Newtown Food Festival Community Interest Company | Administrative & support | 2019 |
| Newtown Food Surplus | Hospitality | 2021 |