| Kounga Developments Ltd | Construction | 2018 |
| Koyo Cars Ltd | Wholesale & retail | 2026 |
| Ksbna/Bloomsbury Limited | Health & social care | 2020 |
| Kursat’S Ltd | Manufacturing | 2025 |
| L & G Consultancy Ltd | Professional & scientific | 2021 |
| LAS Pozas Ltd | Information & communication | 2014 |
| Laser TAG FEC Limited | Other services | 2024 |
| Laura Beth Events Ltd | Administrative & support | 2025 |
| LCF Holidays Limited | Hospitality | 2022 |
| LD3 Limited | Agriculture & fishing | 2013 |
| Ldkk Ltd | Hospitality | 2018 |
| Learn My Craft Limited | Information & communication | 2024 |
| Legacy Journeys Ltd | Administrative & support | 2024 |
| Lenny Agrimedico Services Ltd | Agriculture & fishing | 2016 |
| Lewis Lets Limited | Real estate | 2017 |
| Lili Rose Consultancy Cyfyngedig | Health & social care | 2024 |
| Lime Plastering Wales Limited | Construction | 2020 |
| Lime Tree Park Limited | Construction | 2003 |
| Lindley Johnstone Limited | Real estate | 1996 |
| Linklater Properties Limited | Real estate | 1952 |
| Links Marketplace Ltd | Wholesale & retail | 2025 |
| Little Wander Limited | Information & communication | 2010 |
| Llanfaes Dairy Ltd | Wholesale & retail | 2025 |
| Llangorse Caravan Park Limited | Hospitality | 1996 |
| Llangorse Lake Conservation and Management Co. Limited | Real estate | 1986 |
| Llangorse Multi Activity Centre Limited | Hospitality | 2019 |
| Llanwrtyd Wells & District Show Limited | Other services | 2003 |
| Llanwrtyd Wells Land & Estate Co. Limited | Real estate | 1979 |
| Lloydwillsproperties Limited | Real estate | 2019 |
| Lloydy's Building Services Limited | Construction | 2005 |
| Llwynon Saddlery Limited | Manufacturing | 2004 |
| Llyswen and Boughrood Show Limited | Other services | 2022 |
| Llywelyn Holdings Limited | Real estate | 2018 |
| Local Environmental Records Centres Wales Limited | Information & communication | 2015 |
| Lock Stock Holdings Ltd | Financial services | 2022 |
| Locksmart BMC Ltd | Construction | 2014 |
| Long Nursery Coppice Ltd | Real estate | 2025 |
| Lowe Interiors Limited | Wholesale & retail | 2024 |
| LP Trucks (Hereford) Limited | Wholesale & retail | 2026 |
| Lpsp Limited | Real estate | 2025 |
| Lucy Eyre Limited | Arts & recreation | 2015 |
| Luxury Border Barns Ltd | Hospitality | 2020 |
| Luxury Border Cottages Limited | Hospitality | 2015 |
| Lyndhurst Property Development Limited | Real estate | 2001 |
| Lyndon Lewis Ltd | Professional & scientific | 2013 |
| M and K Environmental Ltd | Administrative & support | 2021 |
| M H Davies Contractors Limited | Construction | 2003 |
| M J Transport (Powys) Limited | Transport & logistics | 2019 |
| M Jones Agri & Plant Repairs Limited | Manufacturing | 2017 |
| MAC Solutions Plumbing & Heating Limited | Construction | 2012 |
| Mains GAS Limited | Construction | 2019 |
| Make IT Ltd | Wholesale & retail | 2020 |
| Malcolm G. Moon Electrical Limited | Administrative & support | 1999 |
| Malford Consulting Limited | Hospitality | 1996 |
| Manfarm Limited | Professional & scientific | 1980 |
| Mango Homes Ltd | Real estate | 2023 |
| Maricopa Estates Ltd | Real estate | 2024 |
| Mark Stephens Furniture Limited | Manufacturing | 2011 |
| Marsh Harrier Limited | Professional & scientific | 2003 |
| Matharu Eyecare Independent Optometrist Ltd | Other services | 2018 |
| Matt Sampson Restaurants Ltd | Hospitality | 2026 |
| Matthew Smith Design Limited | Manufacturing | 2020 |
| Maughan Enterprises Ltd | Financial services | 2024 |
| Maughan Projects Ltd | Wholesale & retail | 2024 |
| Maughan Rentals Ltd | Real estate | 2024 |
| Maughan Trading Ltd | Real estate | 2024 |
| MAY Street Gardens Investments Limited | Real estate | 2017 |
| MAY Street Gardens Ltd | Administrative & support | 2014 |
| Mbdev Ltd | Information & communication | 2017 |
| MBM Parks Limited | Hospitality | 2021 |
| Mcadorey Property Services Limited | Real estate | 2024 |
| Mccarthy Kitchens and Interiors Ltd | Manufacturing | 2022 |
| MD Carpentry (Brecon) Limited | Construction | 2013 |
| Meadow View (Bronllys) Management Ltd | Extraterritorial | 2010 |
| Medi Dermal Limited | Other services | 2022 |
| Megi Wellness Ltd | Manufacturing | 2023 |
| Melba Trading Limited | Hospitality | 1993 |
| Metal.Mud.Inc. Ltd | Wholesale & retail | 2025 |
| Mick Collins Consultancy Ltd | Administrative & support | 2014 |
| Midwest Plant Group Limited | Construction | 2011 |
| Midwest Plant Limited | Administrative & support | 2011 |
| Midwest Plant Services Ltd | Construction | 2005 |
| Mike Goode & Associates Limited | Professional & scientific | 2003 |
| Mill Service Station Limited | Wholesale & retail | 2011 |
| Millstar Heritage Limited | Construction | 1995 |
| Mjlupo Ltd | Professional & scientific | 2012 |
| Monkslea Limited | Information & communication | 2008 |
| Monolayer Ltd | Professional & scientific | 2021 |
| Morrane Limited | Extraterritorial | 2016 |
| Morvus Technology Limited | Professional & scientific | 2004 |
| Motorcycle Supplies Limited | Wholesale & retail | 2018 |
| Mountain View Equestrian Ltd | Agriculture & fishing | 2023 |
| MPE Applied Technologies Limited | Manufacturing | 2001 |
| Muen Services Limited | Professional & scientific | 2022 |
| Mynydd Marketing Limited | Administrative & support | 2014 |
| N.P.D. Limited | Agriculture & fishing | 1964 |
| Naerok Limited | Transport & logistics | 1983 |
| Nantyffin Cider Mill Limited | Professional & scientific | 2013 |
| Natalka Limited | Professional & scientific | 2015 |
| Nature Child CIC | Other services | 2021 |