| KSB Medics Limited | Health & social care | 2024 |
| KWG Steel Limited | Construction | 2019 |
| L & J Distribution Limited | Wholesale & retail | 2014 |
| L Leafe Construction Limited | Construction | 2024 |
| L R Welsh Limited | Real estate | 2023 |
| L.J. Sales Limited | Wholesale & retail | 2010 |
| LA Metodika Ltd | Wholesale & retail | 2025 |
| LA VIE EN R Ltd | Wholesale & retail | 2025 |
| LAD on Rope Ltd | Mining & quarrying | 2019 |
| LAJ Sales Limited | Wholesale & retail | 2020 |
| Lakshmi Narasimha Swami Ltd | Hospitality | 2025 |
| Lal&Hilal Store Ltd | Wholesale & retail | 2025 |
| Langdales Estates Limited | Real estate | 2004 |
| Larch Rise Ltd | Construction | 2026 |
| LAS Engineering (NE) Ltd | Professional & scientific | 2024 |
| LAS Properties (NE) Ltd | Construction | 2025 |
| LAU Developments Ltd | Real estate | 2021 |
| Lawson Storage Limited | Real estate | 2011 |
| LDG Ltd | Energy | 2021 |
| Leamside Property Limited | Real estate | 2026 |
| Learning at Work Limited | Education | 2007 |
| Learning Curve (NE) Group Limited | Education | 2013 |
| Learning Curve Group Limited | Administrative & support | 2004 |
| Learning Curve Skill Centres Ltd | Education | 2011 |
| Legacy Social Care Ltd | Extraterritorial | 2023 |
| Leinhart Ltd | Wholesale & retail | 2025 |
| LGS Creative Ltd | Professional & scientific | 2022 |
| LH Wind Services Limited | Professional & scientific | 2026 |
| Lighthaus Living Limited | Real estate | 2020 |
| LIJ Sales Limited | Wholesale & retail | 2020 |
| Lika Trade Ltd | Wholesale & retail | 2025 |
| Lily Eden Properties Limited | Real estate | 2022 |
| Linexa Store Ltd | Wholesale & retail | 2026 |
| Lite Rite Solutions Ltd | Manufacturing | 2022 |
| Little Darlings Wrap Around Care Limited | Health & social care | 2015 |
| Livin Developments Limited | Real estate | 2016 |
| LJA Sales Limited | Wholesale & retail | 2013 |
| Lmgm Sales Limited | Wholesale & retail | 2020 |
| Local Shop Group Ltd | Wholesale & retail | 2026 |
| Locktech (NE) Limited | Administrative & support | 2015 |
| London Loungewear Ltd. | Wholesale & retail | 2016 |
| Lrom Environmental Limited | Professional & scientific | 2024 |
| LTW Electrical Ltd | Construction | 2024 |
| Lunova Trade Ltd | Wholesale & retail | 2026 |
| Luther Commissioning Services Ltd | Construction | 2019 |
| Luxe Driveways Ltd | Construction | 2025 |
| Luxenarche Limited | Real estate | 2025 |
| Luxury Leasing Limited | Administrative & support | 2013 |
| Lync Group Ltd | Hospitality | 2023 |
| Lyons Electrical & Plumbing Wholesale Limited | Wholesale & retail | 1998 |
| M G Electrics (N.E.) Limited | Energy | 2010 |
| M Henderson Rolling Stock Limited | Manufacturing | 2018 |
| M&C Prime Ltd | Wholesale & retail | 2025 |
| M.S. & SON Properties Ltd | Real estate | 2020 |
| MA Neocommerce Ltd | Wholesale & retail | 2026 |
| Mabisiv Ltd | Wholesale & retail | 2026 |
| Macron Solutions Limited | Financial services | 2026 |
| Maculume Limited | Manufacturing | 2014 |
| Maddison Financial Planning Ltd | Financial services | 2022 |
| Maddison Mckenna Ltd | Other services | 2025 |
| Magdora Trade Ltd | Wholesale & retail | 2026 |
| Magicalmouse Limited | Hospitality | 2017 |
| Magnesia Ventures Ltd | Wholesale & retail | 2024 |
| Magnificent Trio Ltd | Wholesale & retail | 2026 |
| Malawitech Ltd | Information & communication | 2025 |
| Mall Box Ltd | Wholesale & retail | 2025 |
| Mall Box Trade Ltd | Wholesale & retail | 2025 |
| Mally's Landscaping Ltd | Other services | 2025 |
| Maremco Limited | Administrative & support | 2014 |
| Masala Indian Spice Ltd | Hospitality | 2020 |
| Mason Performance Limited | Wholesale & retail | 2022 |
| Mason S&C Limited | Arts & recreation | 2018 |
| MC Grace Ltd | Construction | 2026 |
| MC Salads Ltd | Wholesale & retail | 2026 |
| Mccarthy Service Group Ltd | Administrative & support | 2024 |
| Mcguinness Property Maintenance Limited | Construction | 2016 |
| Mcnaney Limited | Financial services | 2026 |
| Mcrf Property Company Limited | Real estate | 2015 |
| MDD Associates Limited | Professional & scientific | 2011 |
| MDH Surveys Ltd | Professional & scientific | 2025 |
| Meddle Estates Ltd | Construction | 2019 |
| Mehmet CAN Ertuzun Ltd | Information & communication | 2026 |
| Mehmet Nuri Savas Ltd | Wholesale & retail | 2026 |
| Meikles Solicitors LLP | | 2013 |
| Merrington Plumbing & Heating Services Limited | Construction | 2021 |
| Metay Commerce Ltd | Wholesale & retail | 2026 |
| Metmanis Ltd | Wholesale & retail | 2026 |
| MGL Trade UK Ltd | Other services | 2024 |
| Michael R. Hall Limited | Administrative & support | 2014 |
| Michael Whitwell Limited | Professional & scientific | 2018 |
| Michael's Property Maintenance Services Ltd | Other services | 2016 |
| Michelle Shakallis Ltd | Professional & scientific | 2018 |
| Middleham Developments Ltd | Professional & scientific | 2023 |
| Middlestone Partnership Limited | Real estate | 2023 |
| Middlestone Properties Ltd | Real estate | 2024 |
| Mikos Development Limited | Information & communication | 2012 |
| Milburn Mortgage Solutions Ltd | Financial services | 2026 |
| Minnikin Flooring Solutions Ltd | Construction | 2026 |
| Minnikin Holdings Ltd | Real estate | 2026 |
| Misty Blue Farm Limited | Agriculture & fishing | 2021 |