| Klendda Limited | Wholesale & retail | 2022 |
| Klenton Ltd | Wholesale & retail | 2022 |
| KM Medical Partners Ltd | Health & social care | 2026 |
| Knapp-Haul Limited | | 1973 |
| Knit & Ting Ltd | Manufacturing | 2022 |
| Koch-Light Laboratories Limited | | 1936 |
| Kohh Ltd | Wholesale & retail | 2021 |
| Kololi Travel Limited | Real estate | 2003 |
| Koolgp Technology Co., Ltd | Manufacturing | 2025 |
| Korean Beauty Secret Ltd | Wholesale & retail | 2024 |
| Kova Associates Ltd | Wholesale & retail | 2019 |
| Kreative Koncept Ltd | Wholesale & retail | 2023 |
| Kreativekat Ltd | Wholesale & retail | 2020 |
| KTL4 Limited | Information & communication | 2022 |
| Ktmmr Ltd | Wholesale & retail | 2026 |
| Kuphila Group Limited | Wholesale & retail | 2022 |
| Kurikkol BIO Ltd | Professional & scientific | 2023 |
| Kwan Thai (Ipswich) Limited | Hospitality | 2003 |
| L'Avenir Properties Ltd | Financial services | 2018 |
| L.A.C. Cleaning Contractors Limited | Administrative & support | 2005 |
| L.C.Green & Son(Beccles)Limited | Wholesale & retail | 1962 |
| L.S. Eaves Limited | Wholesale & retail | 1958 |
| Laanua Collective Ltd. | Extraterritorial | 2025 |
| Labas Consulting Ltd | Professional & scientific | 2023 |
| Lablogix Ltd | Professional & scientific | 2024 |
| Lais Commercial Enterprise LLP | | 2023 |
| Lamberts Service Station Limited | Wholesale & retail | 2003 |
| Lampwick Care Limited | Health & social care | 2009 |
| Lampwick Developments Limited | Real estate | 2006 |
| Langton Park Management Company Limited | Real estate | 2003 |
| Lardner Building and Stoves Limited | Construction | 2011 |
| Lateral Media Limited | Professional & scientific | 2005 |
| Lauren Potter Holistic Therapy Centre Ltd | Other services | 2025 |
| Laurence Walter Limited | Other services | 2006 |
| Lavenham Press Limited(The) | Manufacturing | 1953 |
| LCM Logistics Limited | Transport & logistics | 2025 |
| LCM Specialist Services Limited | Administrative & support | 2012 |
| Lcsp Register of Remedial Masseurs and Manipulative Therapists | Other services | 2001 |
| LE Pozi Ltd | Hospitality | 2022 |
| Leacky's Pride Limited | Health & social care | 2015 |
| Leading Edge Aviation Maintenance Consultancy Ltd | Manufacturing | 2015 |
| Ledge Trading Limited | Arts & recreation | 2023 |
| Legacies Estate Ltd | Real estate | 2022 |
| Leilaandco. Cleaning Services Ltd | Administrative & support | 2023 |
| Leinster Estate Limited | Real estate | 2021 |
| Leiston Plant Hire Limited | Construction | 1974 |
| Leisure 7 Ltd | Wholesale & retail | 2010 |
| Lettergold Asset Management Limited | Real estate | 1987 |
| Lettergold Plastics Limited | Manufacturing | 1993 |
| Lettergold Water Treatment Solutions LLP | | 2007 |
| Leul Ltd | Wholesale & retail | 2019 |
| Level Access Ltd | Construction | 2024 |
| Libra Brands Limited | Information & communication | 2023 |
| Life Resolutions Limited | Health & social care | 2006 |
| Lifesize Trading Limited | Wholesale & retail | 2005 |
| Lifestyle Trade Limited | Wholesale & retail | 2023 |
| Lighting for Life Ltd | Manufacturing | 2019 |
| Lighting G.B. Limited | Wholesale & retail | 2004 |
| Lightning Trucks Ltd | Transport & logistics | 1998 |
| Limepro Limited | Professional & scientific | 2023 |
| Ling - Robertson Limited | Arts & recreation | 2006 |
| Liskion Ltd | Information & communication | 2018 |
| Little GEM Hygiene Specialists Limited | Administrative & support | 2006 |
| Little Indie Limited | Information & communication | 2009 |
| Livo Ltd | Wholesale & retail | 2008 |
| Liwave International Limited | Wholesale & retail | 2024 |
| Lloyd & Co Property Ltd | Real estate | 2024 |
| LML Installs Limited | Arts & recreation | 2023 |
| Load and Lift (Ipswich) Limited | Transport & logistics | 2002 |
| Lockpark Limited | Transport & logistics | 1995 |
| Logicly Ltd | Information & communication | 2013 |
| Logistic Planning Services Limited | Transport & logistics | 1996 |
| London Waste Services Ltd | Water & waste | 2018 |
| Look Smart Barber Ltd | Administrative & support | 2016 |
| Look&See Limited | Professional & scientific | 2024 |
| Lord MQ Ltd | Information & communication | 2017 |
| Lords Fields Farms Limited | Agriculture & fishing | 1948 |
| Lowestoft Arts Limited | Arts & recreation | 2000 |
| Lowestoft Fish Producers Organisation Limited | Agriculture & fishing | 1993 |
| LOX (K & L) Limited | Other services | 2004 |
| Lucerna Holdings Limited | Financial services | 2025 |
| Lucky Star Fish & Chips Ltd | Hospitality | 2023 |
| Lucky Union Trade Ltd | Wholesale & retail | 2025 |
| Luxe Steakhouse (Hull) Limited | Hospitality | 2019 |
| LYH Imaging Ltd | Health & social care | 2023 |
| Lynn Star Distribution & Logistics Limited | Transport & logistics | 1993 |
| M a Lyne Motors Limited | Wholesale & retail | 2003 |
| M M I Sportscars Limited | Manufacturing | 2007 |
| M-Mangoes Ltd | Information & communication | 2020 |
| M. W. Nice & Sons Ltd | Administrative & support | 2007 |
| M. W. Nice Limited | Wholesale & retail | 2002 |
| M.F. Last Limited | Construction | 2002 |
| M.S. Surveys Limited | Professional & scientific | 2007 |
| MA Xing Trading Co Ltd | Extraterritorial | 2015 |
| Maddison Investments (Ipswich) Limited | Real estate | 2006 |
| Maiden Resources Limited | Extraterritorial | 2003 |
| Main-Fab Limited | Manufacturing | 1997 |
| Major Incident Management Limited | Education | 2006 |
| MAK Tradezone Limited | Wholesale & retail | 2025 |
| Make & Made Ltd | Information & communication | 2020 |