| Lodge Road Property Partnership Five LP | | 2005 |
| Lodge Road Property Partnership Four L.P. | | 2004 |
| Lodge Road Property Partnership Seven LP | | 2006 |
| Lodge Road Property Partnership SIX L.P. | | 2006 |
| Lodge Road Property Partnership Two | | 2003 |
| Lodgeroad Property Partnership Three LP | | 2004 |
| Loguestown Green Management Company Limited | Extraterritorial | 2010 |
| Lomax Dental Laboratory Ltd | Manufacturing | 2020 |
| Long Meadow Management Company (N.I.) Limited | Households | 2018 |
| Longhorn Steaks Limited | Real estate | 1991 |
| Lopera International Ltd | Wholesale & retail | 2023 |
| Lotus Designs (NI) Ltd | Manufacturing | 2013 |
| Loughbeg Property Management Co. Ltd | Extraterritorial | 2009 |
| Loughview Rentals Limited | Hospitality | 2018 |
| Lower Main Street Management Co Ltd | Extraterritorial | 2016 |
| Lowry's Lane Hospitality Limited | Hospitality | 2018 |
| LR Developments (Derry) Limited | Construction | 2021 |
| Lrbs Investment Limited | Real estate | 2017 |
| Lugico Limited | Education | 2024 |
| Luke Shelf Co 12 Limited | Professional & scientific | 2024 |
| Luna Point Wellness Ltd | Other services | 2024 |
| Luxmedics N.I Limited | Professional & scientific | 2026 |
| Lynas Foods | Professional & scientific | 2004 |
| M-Prove Solutions Limited | Administrative & support | 2024 |
| M-Tech Mechanical Ltd | Construction | 2018 |
| M.E.G. Cards and Gifts Ltd | Wholesale & retail | 2018 |
| M.E.G. Cards and Gifts Wholesale Ltd | Wholesale & retail | 2019 |
| Macaulay Wray LLP | | 2012 |
| Machinery and Plant Sales Ltd | Wholesale & retail | 2025 |
| Macino Ltd | Extraterritorial | 2013 |
| Madb Medical Ltd | Health & social care | 2011 |
| Made UP North Ltd | Wholesale & retail | 2021 |
| Mahood Floral Ltd | Wholesale & retail | 2001 |
| Main Street (Tobermore) Management Company Limited | Households | 2006 |
| Maine Group Ltd | Financial services | 2019 |
| Maine Plant and Equipment Ltd | Professional & scientific | 2019 |
| Maine Surface Finishing Limited | Manufacturing | 2006 |
| Makini Enterprises Limited | Health & social care | 2014 |
| Makini Health Care Limited | Health & social care | 2016 |
| Malgas Investments Ltd | Manufacturing | 2025 |
| Malico Limited | | 1999 |
| Mambo Marketing Ltd | Professional & scientific | 2025 |
| MAN Friday Property Solutions Ltd | Other services | 2025 |
| Manafin Ltd | Transport & logistics | 2019 |
| Managet Lian Limited | Wholesale & retail | 2025 |
| Manannan Ltd | Professional & scientific | 2025 |
| Marine Apartments Management Company Limited | Households | 2005 |
| Marinecore Civils Ltd | Professional & scientific | 2025 |
| Market Street Management Company Limited | Households | 2007 |
| Market Yard Management Company Limited | Households | 2005 |
| Marshall Howe Greengrocer & Florist Ltd | Wholesale & retail | 2010 |
| Martin King French & Ingram Ltd | Professional & scientific | 2025 |
| Martin Mcilvar & Sons Limited | Construction | 2017 |
| Martius Developments Ltd | Construction | 2020 |
| Mary Louise Mckeag Ltd | Wholesale & retail | 2017 |
| Master Key Developments Ltd | Real estate | 2020 |
| Matei Training Ltd | Education | 2026 |
| Mathewson Square Ltd | Construction | 2016 |
| MAX Snax Limited | Wholesale & retail | 2002 |
| Mazi Energy Ltd | Information & communication | 2026 |
| MC Consultancy Ltd | Information & communication | 2025 |
| Mcauley Tree Surgery Ltd | Administrative & support | 2024 |
| Mcbride Contracts Ltd | Construction | 2007 |
| Mcbride Plant Hire Ltd | Administrative & support | 2020 |
| Mcclartys Limited | Financial services | 2015 |
| Mcclean Homes Limited | Real estate | 2016 |
| Mccollum Lawns Ltd | Administrative & support | 2017 |
| MCF Charitable Trust - the | Other services | 1999 |
| MCG Groundworks Ltd | Construction | 2021 |
| Mcgarry-Moon Architects Ltd | Professional & scientific | 2004 |
| Mcgilligan Kitchens & Joinery Ltd | Construction | 2021 |
| Mcgrath Tree Surgery Ltd | Administrative & support | 2018 |
| MCI Consultancy Ltd | Professional & scientific | 2024 |
| Mcilroy Farms Limited | Agriculture & fishing | 2016 |
| Mcintosh Solicitors Limited | Professional & scientific | 2016 |
| Mckeag & Co. Limited | Health & social care | 1997 |
| Mckendry Fabrication & Construction Ltd | Financial services | 2019 |
| Mckendry Fabrication & Construction Services Ltd | Construction | 2019 |
| Mckillop and Sons Ltd | Hospitality | 2026 |
| Mclaughlin Drylining Ltd | Construction | 2015 |
| MCN Group UKI Limited | Financial services | 2026 |
| Mczhangley Investments Ltd | Real estate | 2026 |
| Meadowfield Development Limited | Construction | 2004 |
| Meadowhill (Drumlegagh) Land Management Ltd | Households | 2019 |
| Meath Park Livery Ltd | Agriculture & fishing | 2025 |
| Meenakshi Transportation Ltd | Transport & logistics | 2024 |
| Mellowvelo Consultancy Ltd | Education | 2016 |
| Melodic Elements Ltd | Professional & scientific | 2019 |
| MEM Plumbing Ltd | Construction | 2009 |
| Merlin Inspection Services Ltd | Professional & scientific | 2022 |
| Mervyn Crean Building & Joinery Ltd | Construction | 2004 |
| MG Collective Ltd | Arts & recreation | 2020 |
| MI Design Studio LLP | | 2022 |
| Michael D Properties Limited | Real estate | 2024 |
| Micro Learning Labs Limited | Education | 2024 |
| Micro-Flexitronics Limited | | 2007 |
| Middlebrook Property Rentals Ltd | Real estate | 2022 |
| Mildun Haulage Limited | Transport & logistics | 2003 |
| Mill Court Development Management Limited | Households | 2004 |
| Mill Lane (Augher) Management Ltd | Households | 2022 |