| L F Jarvis and SON Limited | Construction | 1997 |
| L R Sladen Consulting Limited | Professional & scientific | 2017 |
| L&M Driver Ltd | Transport & logistics | 2025 |
| L-Fast Holdings Limited | Professional & scientific | 2020 |
| L.V. Ward (Farm Produce) Limited | Wholesale & retail | 1952 |
| LA Didor Lingerie Limited | Wholesale & retail | 2019 |
| LA Stories Limited | Information & communication | 2017 |
| Laburnum Road 1960 Limited | Extraterritorial | 2014 |
| Laing PD Limited | Construction | 2024 |
| Lake Isle Ltd | Information & communication | 2017 |
| Landscope Land and Property Limited | Professional & scientific | 2014 |
| Lane & Browns Limited | Real estate | 2016 |
| Lanes Residential Ltd | Real estate | 2022 |
| Lansley's Landscape Centre Ltd | Wholesale & retail | 2025 |
| Lansley’S Holdings Ltd | Financial services | 2025 |
| Larks Motor Group Ltd | Wholesale & retail | 2021 |
| Leadlike Consulting Ltd | Professional & scientific | 2026 |
| LEE Roofing Limited | Construction | 2000 |
| LEE Trees Ltd | Agriculture & fishing | 2003 |
| Leeyaan Ltd | Wholesale & retail | 2024 |
| Legitimate Animal Ltd | Professional & scientific | 2018 |
| LEO Linear Limited | Information & communication | 2017 |
| Lewis Andersen Limited | Professional & scientific | 2011 |
| Lexis (Biggleswade) Limited | Administrative & support | 2013 |
| Lgph Limited | Construction | 2019 |
| LH Sales Ltd | Wholesale & retail | 2025 |
| Liberty Ridge Creatives Ltd | Information & communication | 2018 |
| Lightning Investments Limited | Real estate | 2014 |
| Like Lightning Ltd | Information & communication | 2024 |
| Lily Grey Limited | Information & communication | 2012 |
| Limeculture Solutions Limited | Professional & scientific | 2025 |
| Lincoln Coaching Ltd | Professional & scientific | 2024 |
| Lincoln York Ltd | Professional & scientific | 2019 |
| Linnet Consultancy Ltd | Wholesale & retail | 2018 |
| Lion Court (Potton) Management Co. Limited | Households | 1984 |
| Lipstick Rebel Productions Ltd | Arts & recreation | 2019 |
| Little BIT Productions Limited | Information & communication | 2017 |
| Little Film Productions Limited | Information & communication | 2021 |
| Little Grey London Limited | Wholesale & retail | 2018 |
| Little Staughton Farms Limited | Agriculture & fishing | 1985 |
| Little Wrigglers Ltd | Health & social care | 2024 |
| Lluna Ltd | Wholesale & retail | 2012 |
| Lluxx Ltd | Real estate | 2019 |
| Lmor Ltd | Manufacturing | 2024 |
| Loaded Clip Productions Limited | Information & communication | 2022 |
| Loaden Haulage Ltd | Transport & logistics | 2023 |
| Logic Apps Ltd | Extraterritorial | 2014 |
| Logisoft Limited | Information & communication | 1998 |
| London Electronics Limited | Manufacturing | 1992 |
| Long Grain Films Ltd | Information & communication | 2010 |
| Long Story Short Limited | Information & communication | 2012 |
| Longfield Court Management Limited | Professional & scientific | 1988 |
| Lordace Services Ltd | Health & social care | 2026 |
| Loryservices Ltd | Professional & scientific | 2024 |
| Lowe Fraser Finance Limited | Professional & scientific | 2019 |
| Lowe Fraser Holdings Limited | Financial services | 2024 |
| Lowe Fraser Limited | Professional & scientific | 2015 |
| Lowe Fraser Property Limited | Real estate | 2023 |
| LSF Creative Ltd | Health & social care | 2021 |
| Lucky Cat TV Ltd | Information & communication | 2014 |
| Lucky Wrench Ltd | Wholesale & retail | 2025 |
| Lumpi Limited | Manufacturing | 2012 |
| Lunal Properties Limited | Real estate | 2020 |
| Lush Digital Media Limited | Manufacturing | 2014 |
| Lysander Place Group Limited | Professional & scientific | 2014 |
| Lysander Place Holdings Limited | Professional & scientific | 1999 |
| M Branco Services Limited | Construction | 2025 |
| M Performance Solutions Ltd | Construction | 2026 |
| M.P.S. Concrete Solutions Limited | Construction | 2013 |
| Maacare Health Ltd | Health & social care | 2023 |
| Macintyres UK Ltd | Wholesale & retail | 2008 |
| Madison Jackman Limited | Other services | 2015 |
| Make Film & Television Ltd | Information & communication | 2009 |
| Making Every Adult Matter Services Ltd | Health & social care | 2019 |
| Manor Carpentry Limited | Construction | 1997 |
| Manor Concepts Limited | Administrative & support | 2007 |
| Mansfield Mews (Flats) Management Limited | Households | 2002 |
| Mara HGV Ltd | Transport & logistics | 2024 |
| March Farmers (Washland) Limited | Agriculture & fishing | 1972 |
| Marco Ents Limited | Information & communication | 2024 |
| Maritsa D'Almeida Ltd | Health & social care | 2015 |
| Market Square Potton Management Company Limited | Households | 1980 |
| Market Square Properties Limited | Real estate | 2009 |
| Martha S Film Yard Limited | Information & communication | 2007 |
| Masterteck Repair Ltd | Construction | 2019 |
| Masway Construction Limited | Construction | 2018 |
| Masway Property Limited | Real estate | 2024 |
| Maxicab Hair Ltd | Other services | 2025 |
| Maxillo-Facial Limited | Health & social care | 2017 |
| Mbawheels Ltd | Manufacturing | 2026 |
| MBS Architectural Group Ltd | Construction | 2020 |
| MBS Architectural Limited | Construction | 2017 |
| MCB Settlement Trust Company Limited | Professional & scientific | 2003 |
| Meadowview Media Limited | Professional & scientific | 2018 |
| Mearl Music Limited | Arts & recreation | 2010 |
| Medologyuk Ltd | Health & social care | 2025 |
| Meetvox AI Limited | Information & communication | 2026 |
| Meissner Film Limited | Information & communication | 2019 |
| Meliora Financial Planning Limited | Professional & scientific | 2023 |
| Mella Homecare Ltd | Health & social care | 2025 |