| Krishna Pharma Ltd | Health & social care | 2010 |
| Krispr Technologies Limited | Professional & scientific | 2021 |
| Kundalini Yoga Teachers' Association | Other services | 2016 |
| Kusumaya Limited | Health & social care | 2021 |
| L Faers Ltd | Administrative & support | 2015 |
| Ladbroke Gardens Management Limited | Professional & scientific | 1996 |
| Ladywolf Consulting Limited | Information & communication | 2017 |
| Lakeside Close Residents' Association Limited | Households | 1981 |
| Landmark Faith Recruiting Solutions Ltd | Administrative & support | 2012 |
| Laurel Gardens Freehold Ltd | Administrative & support | 2018 |
| Lavender Grange Management Company Limited | Households | 1994 |
| Leaf Lobster Limited | Professional & scientific | 2015 |
| Learn to Thrive Ltd | Wholesale & retail | 2010 |
| Learnik Ltd | Information & communication | 2024 |
| Lets DO the Right Thing Ltd | Professional & scientific | 2018 |
| Letters and Numbers Limited | Extraterritorial | 2009 |
| Lewis Parnell Limited | Administrative & support | 2009 |
| Lilliput Avenue Northolt Management Limited | Households | 1985 |
| Link Way RTM Company Limited | Households | 2004 |
| Lion Publishing Ltd | Information & communication | 2020 |
| Lionel Avenue (Wendover) Management Company Limited | Real estate | 2017 |
| Little Willows Psychology Ltd | Education | 2025 |
| London Centre of Reproductive Health (Lcrh) Limited | Health & social care | 2024 |
| London Couture Limited | Professional & scientific | 2004 |
| London Ehrmann Ltd | Wholesale & retail | 2017 |
| Long Gables Management Company Limited | Households | 2006 |
| Longcroft (GX) Management Company Limited | Households | 2006 |
| Love Rentals Limited | Real estate | 2014 |
| Lovund Limited | Information & communication | 2021 |
| Lower Road Chorleywood Management Limited | Households | 1987 |
| Lumino Dental Ltd | Health & social care | 2017 |
| Lungley Property Services Limited | Real estate | 2025 |
| Lush Gaming Consultancy Limited | Arts & recreation | 2018 |
| Luxe Strategy International Limited | Wholesale & retail | 2020 |
| Luxury Connect Africa Limited | Wholesale & retail | 2019 |
| Lydia Harrison Ltd | Real estate | 2025 |
| Lydia Lodge Residents Limited | Households | 2020 |
| Lysk Properties Limited | Real estate | 2023 |
| M H Hydraulics Ltd | Manufacturing | 2016 |
| M2M Logistics Limited | Administrative & support | 2012 |
| Mackco Ltd | Administrative & support | 2024 |
| Main Event Enterprises Ltd | Hospitality | 1988 |
| Make IT Tennis Ltd | Arts & recreation | 2024 |
| Malalapipe Limited | Construction | 2006 |
| Manel Partners Limited | Hospitality | 2018 |
| Manyfest Ltd | Wholesale & retail | 2021 |
| Maple Heights (Residents) Limited | Other services | 1986 |
| Marian Arts Psychotherapy Ltd | Health & social care | 2023 |
| Maridnach Limited | Information & communication | 2011 |
| Martynvestments Limited | Construction | 2022 |
| Martyrs Court Company Limited | Households | 1967 |
| Mary Louise Clark Associates Limited | Information & communication | 2006 |
| Marylebone Communications Ltd | Professional & scientific | 2020 |
| Matilda Cakes Ltd | Wholesale & retail | 2025 |
| Maxian Ltd | Wholesale & retail | 2018 |
| Mayo Haulage Limited | Transport & logistics | 2006 |
| Mcclymont Heaton Consulting Ltd | Professional & scientific | 2015 |
| MCM Computer Systems Limited | Information & communication | 1997 |
| MDB Junction Limited | Financial services | 2019 |
| Meadow Bank Close Apartments Limited | Real estate | 2006 |
| Meadow Bank Close Limited | Real estate | 2006 |
| Mebazov Ltd | Wholesale & retail | 2025 |
| Mechlineuk Ltd | Manufacturing | 2024 |
| Media Arcade Ltd | Professional & scientific | 2025 |
| Medical Solutions Delivered Ltd | Health & social care | 2000 |
| Meldale Limited | Real estate | 1999 |
| Metallurgical and Associated Services Limited | Professional & scientific | 2002 |
| MG Travel Advisers Ltd | Administrative & support | 2026 |
| Mhgh Limited | Administrative & support | 2026 |
| Middlegate Services Ltd | Administrative & support | 1998 |
| Midsummer Court Hazlemere Management Limited | Households | 2002 |
| Midsummer Court Staines Management Company Limited | Real estate | 2013 |
| Midsummer Place (Bicester) Management Limited | Households | 2005 |
| Minds EYE Brewing Community Interest Company | Manufacturing | 2021 |
| Mining and Materials Markets Ltd | Professional & scientific | 2024 |
| Misbourne Estates Limited | Construction | 2018 |
| Miss Fish Bar Ltd | Hospitality | 2025 |
| Missenden Holdings Limited | Information & communication | 2020 |
| Missenden LLP | | 2010 |
| Mitchell Family Investments Limited | Real estate | 2019 |
| MMH Consultancy Limited | Administrative & support | 2017 |
| Moat Drive Limited | Households | 1994 |
| MONEY4MACHINES Ltd | Administrative & support | 2010 |
| Montesole Court Residents Limited | Households | 1993 |
| More Than YOU Think Ltd | Professional & scientific | 2014 |
| More Wealth Planning Ltd | Financial services | 2014 |
| Moreland Associates Ltd | Professional & scientific | 2026 |
| Moster Science Limited | Information & communication | 2021 |
| Mullered Ltd | Information & communication | 2022 |
| My Product Life Ltd | Information & communication | 2024 |
| Myth Inc. Limited | Professional & scientific | 2018 |
| Nanfans Ballet School Limited | Arts & recreation | 2015 |
| Neuroadapt Ltd | Health & social care | 2023 |
| Newvale Trading Limited | Hospitality | 2014 |
| Nicholas Noke Limited | Construction | 2013 |
| NM Hanekom Ltd | Health & social care | 2011 |
| Nomad Resources Limited | Professional & scientific | 2008 |
| Nombus Limited | Arts & recreation | 2021 |
| Noor Safia | Other services | 2013 |
| Noor Safia Management Ltd. | Wholesale & retail | 2005 |