| Kamry Properties Limited | Real estate | 2001 |
| Kawaii KAT Ltd | Wholesale & retail | 2025 |
| Keith Turner Motors Limited | Wholesale & retail | 1971 |
| Kensington Realty Corporation Limited | Real estate | 2015 |
| KEO (UK) Limited | Administrative & support | 1993 |
| Keshav Asset Holding 1 Limited | Real estate | 2026 |
| Kessel Construction (UK) Limited | Construction | 2014 |
| Kirsten Grant Consultancy Limited | Professional & scientific | 2012 |
| Kissous LLP | | 2020 |
| Kitch Unlocked Ltd | Education | 2026 |
| KK Cabs Limited | Transport & logistics | 2016 |
| Kmbeats Enterprises Ltd | Information & communication | 2013 |
| Kounnis Group Limited | Real estate | 1980 |
| Krish Pharma Ltd | Health & social care | 2016 |
| Kyprioth Ltd | Information & communication | 2023 |
| Kyra Pret Ltd | Wholesale & retail | 2020 |
| Laamu Properties Ltd | Real estate | 2018 |
| Lahori Halal Meat Ltd | Wholesale & retail | 2025 |
| Lambs Cafe Limited | Hospitality | 2020 |
| Landau Way RTM Company Ltd | Other services | 2014 |
| Laser Attraction Ltd | Information & communication | 2018 |
| Laura Emily Lillian Jackson Limited | Information & communication | 2019 |
| Lautön Limited | Wholesale & retail | 2025 |
| Law Consultants Limited | Financial services | 2020 |
| Lcgc | Arts & recreation | 2002 |
| LE Monde Property Limited | Real estate | 2022 |
| LEE Valley Solicitors Ltd | Professional & scientific | 2015 |
| Legacy Property Enterprises Limited | Real estate | 2024 |
| Lena Gardens Ltd | Households | 2021 |
| Lenak Studio Limited | Professional & scientific | 2013 |
| Leslie Franks Investments Limited | Financial services | 2010 |
| Leverage Consultants Limited | Professional & scientific | 2016 |
| Libusa Ltd | Professional & scientific | 2019 |
| Lighthouse Claims Ltd | Administrative & support | 2005 |
| Like Logs Ltd | Construction | 2013 |
| LIL One Limited | Administrative & support | 2010 |
| Lilian Davis Group Care Services Limited | Health & social care | 2021 |
| Lime Auction House Ltd | Real estate | 2016 |
| Linkey Mortgages Ltd | Financial services | 2026 |
| Lipheloservices Ltd | Health & social care | 2023 |
| LIS Properties Limited | Construction | 2012 |
| Logicnet Limited | Information & communication | 2020 |
| Lola London Limited | Information & communication | 2011 |
| Lolly Couture Limited | Administrative & support | 2002 |
| London Homes (UK) Limited | Real estate | 2009 |
| London Residential Services Limited | Administrative & support | 2017 |
| Lorena Flores Limited | Health & social care | 2015 |
| Louvi Limited | Transport & logistics | 2012 |
| LOW Hall Residents Limited | Households | 2004 |
| LRC Design Limited | Professional & scientific | 2022 |
| LRC Plants Limited | Wholesale & retail | 2022 |
| LSD Retail Ltd | Wholesale & retail | 2025 |
| Luna Stone Italia Limited | Financial services | 2011 |
| Lunar Module Limited | Other services | 2024 |
| Lura Environment Ltd | Water & waste | 2025 |
| Luxury Apparel Limited | Wholesale & retail | 2020 |
| Lynk Management Consultants Limited | Professional & scientific | 2001 |
| Lynx Global Holdings Limited | Financial services | 2025 |
| Lynx Global Ltd | Transport & logistics | 2020 |
| Lynx Transport Ltd | Wholesale & retail | 2015 |
| M & K Properties (London) LLP | | 2024 |
| M Angel Infotech Ltd | Information & communication | 2023 |
| M S Ramsey Ltd | Real estate | 2018 |
| M-Car Consultancy Services Ltd | Construction | 2024 |
| M.J.N.S. Interiors Limited | Professional & scientific | 2024 |
| Mahanayim Publications and Bible Shop Ltd | Wholesale & retail | 2020 |
| MAK Shopora Ltd | Wholesale & retail | 2026 |
| Maksx Limited | Transport & logistics | 2012 |
| Malibu Salon Ltd | Other services | 2023 |
| Manes Global Ltd | Professional & scientific | 2022 |
| Marali Management Limited | Professional & scientific | 2025 |
| Margaret Benjamin Consulting Ltd | Information & communication | 2014 |
| Mario Fitness Ltd | Education | 2007 |
| Marketing Fuel Ltd | Professional & scientific | 2020 |
| Markou Properties Limited | Real estate | 2018 |
| Masons Investment London Ltd | Other services | 2015 |
| Maverick Publicity Limited | Professional & scientific | 2014 |
| MAY Properties Limited | Real estate | 2014 |
| Mbeed Ltd | Wholesale & retail | 2021 |
| MCA Design Ltd | Information & communication | 2026 |
| MDR Communications Limited | Professional & scientific | 2016 |
| Medinox (London) Limited | Wholesale & retail | 2018 |
| Megaron Enterprises Limited | Financial services | 2018 |
| Meggs, Costoya, Attfield Limited | Administrative & support | 1998 |
| Melanie Christina Group Ltd | Administrative & support | 2019 |
| Melbrian Limited | Wholesale & retail | 1979 |
| Mellon Brands Limited | Professional & scientific | 2013 |
| Mercury Investments Limited | Real estate | 2011 |
| Mercury Safety and Compliance Limited | Administrative & support | 2025 |
| Meseme Studio Ltd | Manufacturing | 2023 |
| MHH Properties Ltd | Construction | 2025 |
| Michal/Laura LLP | | 2026 |
| Migeta Limited | Real estate | 2025 |
| Miller & Co. (Retail) Limited | Wholesale & retail | 2018 |
| Mimis Property Limited | Real estate | 2020 |
| Minds Holdings Limited | Financial services | 2023 |
| Minds Hotels Limited | Hospitality | 2013 |
| Minds Investments Limited | Real estate | 2023 |
| Mitchell Egan Duffy (MED) Limited | Administrative & support | 2017 |
| Mitchell Pitts Vending Limited | Administrative & support | 1999 |