| LTR 14 Limited | Real estate | 2023 |
| LTR 6 Limited | Extraterritorial | 2015 |
| LTR 9 Limited | Real estate | 2022 |
| LTR Freehold (Brandon) Limited | Real estate | 2021 |
| LTR Freehold (Dylon) Limited | Real estate | 2021 |
| LTR Freehold 2 Limited | Real estate | 2016 |
| LTR Freehold 3 Limited | Real estate | 2016 |
| LTR Freehold Limited | Real estate | 2010 |
| LTR Ground Rents 5 Limited | Real estate | 2016 |
| LTR Ground Rents 8 Limited | Extraterritorial | 2017 |
| LTR Rooftop Developments Limited | Extraterritorial | 2016 |
| LU BAN Foundation | Education | 2020 |
| Lucas Estates & Developments Ltd | Financial services | 2025 |
| Lucas Fines Limited | Real estate | 2025 |
| Lucinda James Ltd | Other services | 2010 |
| Lucy & Co (London) Limited | Construction | 2025 |
| Lucy & Co (UK) Limited | Construction | 2006 |
| Lucy & Co LLP | | 2003 |
| Lucy Simpson Services Limited | Other services | 2017 |
| Lulus Pantry Limited | Manufacturing | 2025 |
| Luma Construction Group Limited | Construction | 2022 |
| Lumara Financial Ltd | Financial services | 2025 |
| Luna Mars Living Ltd | Wholesale & retail | 2023 |
| Luna Rain Properties Limited | Real estate | 2024 |
| Lunacap Holdings Limited | Administrative & support | 2025 |
| Lundon Limited | Manufacturing | 2014 |
| Lure Ltd | Administrative & support | 2020 |
| Lusimel Ltd | Health & social care | 2012 |
| LUX Labs Limited | Real estate | 2019 |
| LUX Logburners Limited | Construction | 2026 |
| LUX Woodburners Ltd | Construction | 2025 |
| Luxe Mattresses Limited | Manufacturing | 2025 |
| Luxe Premier Group Ltd | Wholesale & retail | 2025 |
| Luxudor Ltd | Professional & scientific | 2020 |
| Luxury Lounge Official Ltd | Wholesale & retail | 2022 |
| LW Carpentry & Construction Ltd | Construction | 2025 |
| LW Haulage Ltd | Transport & logistics | 2025 |
| LWD Subsea Engineering Ltd | Professional & scientific | 2024 |
| LYN & Co Limited | Health & social care | 2023 |
| Lynos Limited | Professional & scientific | 2026 |
| Lythalls Place (Coventry) Management Company Limited | Households | 2016 |
| M & a Lewis Co Ltd | Professional & scientific | 2024 |
| M & N Construction Staffing Ltd | Administrative & support | 2026 |
| M & T 84 Ltd | Transport & logistics | 2018 |
| M and Z Hires Limited | Transport & logistics | 2023 |
| M Blue Ltd | Wholesale & retail | 2007 |
| M Dawkins Ltd | Financial services | 2021 |
| M Heaney Electrical Limited | Construction | 2016 |
| M J B Engineering (Essex) Limited | Professional & scientific | 2014 |
| M L F Surveying & Setting OUT Services Limited | Professional & scientific | 2014 |
| M Property Finance Ltd | Financial services | 2022 |
| M R Bernier Advisers Limited | Financial services | 2020 |
| M R Brothers Limited | Hospitality | 2020 |
| M&F Health Tourism Ltd | Public administration | 2019 |
| M&F Tour Services Limited | Administrative & support | 2023 |
| M&K Hover Systems Ltd | Professional & scientific | 2023 |
| M&L Signmakers Limited | Manufacturing | 2013 |
| M-Body Media and Events Ltd | Wholesale & retail | 2020 |
| M. R. Ullah Properties Limited | Administrative & support | 2017 |
| M.A.Naska Limited | Health & social care | 2015 |
| M.R.B. Solutions Limited | Information & communication | 1998 |
| MA Consultants Services Ltd | Information & communication | 2018 |
| MAA Tech Solutions Limited | Wholesale & retail | 2015 |
| MAC Marketing and Promotions Limited | Administrative & support | 2024 |
| Macey Property Holdings Ltd | Real estate | 2022 |
| Macmillan Browne Limited | Professional & scientific | 2017 |
| Macro Consultants Ltd | Professional & scientific | 2021 |
| Macrory Digital Limited | Information & communication | 2026 |
| Madcap Property Ltd | Real estate | 2021 |
| Madlee Ltd | Real estate | 2024 |
| Mador & Partners Chartered Architects Ltd | Professional & scientific | 2007 |
| Magic Find Coaching Ltd | Information & communication | 2020 |
| Magic Office Limited | Information & communication | 2016 |
| Magnus Design Limited | Real estate | 1991 |
| Magnus Midland Limited | Real estate | 1991 |
| Magpie Careuk Limited | Administrative & support | 2023 |
| Magpie East Consultancy Limited | Professional & scientific | 2021 |
| Magpie Healthcare Limited | Public administration | 2020 |
| Maiax Limited | Construction | 2011 |
| Maiden Vale (Ryhope) Management Company Limited | Households | 2015 |
| Maidstone Communications Limited | Information & communication | 2007 |
| Main Road Garage (Billericay) Limited | Wholesale & retail | 2000 |
| Maintenance Commercial Services Ltd | Professional & scientific | 2025 |
| Majestic Solutions Ltd | Health & social care | 2009 |
| Make ME Glam Limited | Other services | 2016 |
| Make Your Marketing Better Limited | Education | 2016 |
| MAKE6 Limited | Wholesale & retail | 2022 |
| Makeyo Limited | Health & social care | 2025 |
| Making Complex Simple Ltd | Information & communication | 2025 |
| Makzwie Limited | Health & social care | 2023 |
| Malar Stripe Limited | Professional & scientific | 2025 |
| Malby Lodge Management Company Limited | Households | 1973 |
| Malekos Estates Limited | Real estate | 2002 |
| Malford Estates Ltd | Real estate | 2016 |
| Malio. Ltd | Construction | 2019 |
| Malone Aesthetics Limited | Other services | 2024 |
| Mama's Pizza Ltd | Hospitality | 2019 |
| Mamdal Limited | Information & communication | 2003 |
| Management Labour & Building Services Limited | Construction | 2005 |
| Management Performance Solutions Limited | Administrative & support | 1999 |