| LUV2GROUP Limited | Financial services | 2019 |
| LUV2SELL.COM Limited | Real estate | 2019 |
| LUX Nails & Spa HT Ltd | Other services | 2025 |
| Luxe Gleam Services Ltd | Information & communication | 2025 |
| LWL6 LLC | | 2023 |
| Lydian Holdings Ltd | Financial services | 2023 |
| Lyme Property Group Ltd | Real estate | 2021 |
| Lyme Traders Limited | Transport & logistics | 2025 |
| Lymecastle Mechanical Services Ltd | Construction | 2009 |
| Lynch Living Limited | Real estate | 2017 |
| Lynch Projects Limited | Construction | 2016 |
| Lynville Limited | Financial services | 2025 |
| M & D Marketing Ltd | Manufacturing | 2014 |
| M a Kent Property Services Ltd | Real estate | 2015 |
| M D Accounts and Payroll Ltd | Financial services | 2012 |
| M Downes Plasterers Limited | Construction | 2011 |
| M K Booze Two Limited | Wholesale & retail | 2010 |
| M N Scott Ltd | Construction | 2024 |
| M&D UK Assets Limited | Real estate | 2024 |
| M&G 2016 Ltd | Health & social care | 2024 |
| M&J Hollymount Properties LLP | | 2025 |
| M&L Fast Trans Ltd | Transport & logistics | 2025 |
| M&L Jones Properties Limited | Real estate | 2023 |
| M&S Essentials Ltd | Wholesale & retail | 2023 |
| M.A.Edi Ltd | Construction | 2023 |
| M.E.B. Radiology Ltd | Health & social care | 2024 |
| M.G. Pipework and Fabrications Ltd | Construction | 2024 |
| M.Toner Consulting Ltd | Professional & scientific | 2026 |
| M0HIOTRANSPORT Ltd | Transport & logistics | 2025 |
| M2 Construction (Staffs) Ltd | Construction | 2018 |
| M2 Developments (Staffs) Limited | Construction | 2018 |
| MA Trans Limited | Transport & logistics | 2016 |
| MA UK Pharma Ltd | Professional & scientific | 2020 |
| MA3 Retail Ltd | Wholesale & retail | 2025 |
| Mabel Corp. Ltd | Professional & scientific | 2025 |
| Macaam Consultants Limited | Administrative & support | 2021 |
| Macel Healthcare Service Ltd | Health & social care | 2022 |
| Machine Systems Limited | Wholesale & retail | 2012 |
| Maci Movements Limited | Transport & logistics | 2025 |
| Macken's Inns Ltd | Hospitality | 2026 |
| Mackenzie Isaac Holdings Ltd | Financial services | 2020 |
| Mackenzie Isaac Limited | Wholesale & retail | 2008 |
| MAD Sheep Leasing Ltd. | Financial services | 2012 |
| Mado Cafe Ltd | Hospitality | 2022 |
| Magnolia X Limited | Construction | 2025 |
| Magpi Projects Limited | Information & communication | 2021 |
| Magpie Vintage Tools Limited | Wholesale & retail | 2025 |
| Mahnoor’S Apparel Ltd | Wholesale & retail | 2025 |
| Maidenhair Indoor Plants Ltd | Wholesale & retail | 2025 |
| Mairamax Ltd | Health & social care | 2026 |
| Majestic Credit Limited | Professional & scientific | 2012 |
| MAK Power Ltd | Professional & scientific | 2024 |
| Malone Accounting Limited | Professional & scientific | 2010 |
| Malvern Homes (Walsall) Limited | Construction | 2023 |
| MAN Cave Male Grooming Limited | Other services | 2015 |
| Mandala Corp Limited | Real estate | 2019 |
| Mandelduck Ltd. | Information & communication | 2015 |
| Manor Industrial Engineering Ltd | Professional & scientific | 2024 |
| Mansion House Flats (Stone) Management Company Limited | Real estate | 2016 |
| MAP 4X4 Ltd | Wholesale & retail | 2024 |
| Maple and Mustang Limited | Wholesale & retail | 2025 |
| Maple Court (the Brampton) Limited | Households | 2007 |
| Maple Leaf Landscape Limited | Administrative & support | 2022 |
| Maquay Limited | Other services | 2021 |
| Maranatha NE Ltd | Financial services | 2018 |
| Marceline (Canary Wharf) Limited | Hospitality | 2023 |
| Marcus Residential Properties Limited | Professional & scientific | 2004 |
| Mario Tyers Ltd | Wholesale & retail | 2026 |
| Mark Buxton Estate Agents Ltd | Real estate | 2013 |
| Mark Ginders Limited | Construction | 2016 |
| Mark Joseph Pomelli Limited | Wholesale & retail | 2024 |
| Mark Mason Limited | Construction | 2025 |
| Mark Rafferty Driving Services Limited | Transport & logistics | 2019 |
| Market Place Macclesfield Limited | Real estate | 2025 |
| Market Potential Ltd. | Information & communication | 2014 |
| Marley Housing Limited | Real estate | 2023 |
| Marmaris Ltd | Hospitality | 2024 |
| Marsh Box RTM Company Limited | Households | 2025 |
| Marson Company Holdings Ltd | Wholesale & retail | 2020 |
| Marsz Holdings Limited | Real estate | 2024 |
| Martec Training Limited | Education | 2018 |
| Martian Farms Ltd | Manufacturing | 2020 |
| Martin&George Ltd | Transport & logistics | 2025 |
| Marvel Mortgages & Protection Ltd | Financial services | 2020 |
| Masetech Limited | Information & communication | 2015 |
| Masetech Property Limited | Financial services | 2021 |
| Masons Inns Ltd | Administrative & support | 2024 |
| Master Education Ltd | Administrative & support | 2021 |
| Master Pipe Ltd | Construction | 2016 |
| Matrix Bidco Limited | Financial services | 2017 |
| Matrix Integration Limited | Hospitality | 2003 |
| Matrix Midco 1 Limited | Financial services | 2017 |
| Matrix Midco 2 Limited | Financial services | 2017 |
| Matrix Nominees Limited | Financial services | 2017 |
| Matrix Topco Limited | Financial services | 2017 |
| Matthew Baldwin Property Group Ltd | Households | 2025 |
| Matthew Toner Electrics Ltd | Construction | 2024 |
| Maverick Capital (PT) Limited | Education | 2021 |
| Maverick Marketing Agency Limited | Professional & scientific | 2024 |
| Maxlomax Ltd | Professional & scientific | 2005 |