| Kingsley Healthcare (Olney) Limited | Health & social care | 2021 |
| Kingsley Healthcare (Swaffham) Limited | Health & social care | 2026 |
| Kingsley Healthcare (Weymouth) Limited | Health & social care | 2025 |
| Kingsley Healthcare Limited | Health & social care | 2008 |
| Kingsley Healthcare Management Services Limited | Health & social care | 2016 |
| Kingsley Home Care Services Limited | Health & social care | 2018 |
| Kingsley Nominees Limited | Financial services | 2018 |
| Kingsley PMC Ltd | Extraterritorial | 2014 |
| Kingsley Property Development (ASH) Limited | Health & social care | 2025 |
| Kingsley Property Development (Holt) Limited | Financial services | 2016 |
| Kingsley Property Development (Kessingland) Limited | Health & social care | 2020 |
| Kingsley Property Development (Olney) Limited | Health & social care | 2019 |
| Kingsley Property Development Limited | Construction | 2018 |
| Kingsley Specialist Services (Beccles Property) Limited | Health & social care | 2025 |
| Kingsley Specialist Services (Beccles) Limited | Health & social care | 2024 |
| Kingsley Specialist Services Limited | Administrative & support | 2013 |
| Kingsley Training Academy Limited | Health & social care | 2019 |
| Kinn Barber Ltd | Other services | 2025 |
| Kirkley & Pakefield Community Sports & Social Club Limited | Arts & recreation | 2003 |
| Kirkley House (Lowestoft) Management Company Limited | Households | 1990 |
| Kirkley Power Distribution Services Limited | Energy | 2012 |
| Kirkley Properties Limited | Real estate | 2019 |
| Kistiks Ltd | Wholesale & retail | 2025 |
| KIT Bartram Limited | Other services | 1994 |
| KJ Subsea Limited | Administrative & support | 2019 |
| KJM Vacuum Pump Engineering Limited | Manufacturing | 2022 |
| KK Accountancy Services Ltd | Professional & scientific | 2026 |
| Klass Karaoke Limited | Arts & recreation | 2025 |
| Klyne Family Investments Limited | Professional & scientific | 2024 |
| Klyne Marine Ltd | Agriculture & fishing | 2022 |
| KM Electronics Limited | Construction | 2003 |
| KME Systems Limited | Manufacturing | 2010 |
| Knight Vision Optical Limited | Wholesale & retail | 2003 |
| Knights Estates (Lowestoft) Limited | Real estate | 2026 |
| KO Coach Services Ltd | Transport & logistics | 2026 |
| Kodeblu Limited | Wholesale & retail | 1995 |
| Kore Capital Investments Ltd | Financial services | 2013 |
| KRW Mortgages Limited | Financial services | 2026 |
| KS Fish Limited | Wholesale & retail | 2021 |
| KSL Lifting & Safety Services Limited | Professional & scientific | 2024 |
| KSM Engineering (Suffolk) Ltd | Professional & scientific | 2019 |
| KSM Services Group Limited | Construction | 2017 |
| Kurtis Design Limited | Professional & scientific | 2025 |
| KW Facial Aesthetics Ltd | Other services | 2024 |
| KW Life Solutions Limited | Professional & scientific | 2017 |
| Kyle Dickson Engineering Services Ltd | Professional & scientific | 2025 |
| Kyle Hudson Roofing Ltd | Construction | 2022 |
| L & M Parcel Services Limited | Transport & logistics | 2002 |
| L a C Brickwork Limited | Construction | 2025 |
| L B Plastering Limited | Construction | 2015 |
| L Flower Property Ltd | Real estate | 2020 |
| L Fuller Agricultural Services Ltd | Manufacturing | 2025 |
| L Graham Engineering Ltd | Construction | 2018 |
| L&M Trading Limited | Wholesale & retail | 2010 |
| L.E.C. Marine (Klyne) Limited | Manufacturing | 2005 |
| L.H Services (EA) Ltd | Construction | 2024 |
| Laan Support Services Limited | Construction | 2019 |
| Lace Intervention Limited | Professional & scientific | 2017 |
| Lacons Brewery Limited | Manufacturing | 1993 |
| Lacons Holdings Limited | Professional & scientific | 1996 |
| Lacons PLC | Extraterritorial | 2013 |
| Lake Marina Properties Ltd | Construction | 2020 |
| Lakeside Shops (Blundeston) Limited | Households | 2019 |
| Lakeview Road Pumping Station Limited | Administrative & support | 2025 |
| LAM Groundworks Ltd | Construction | 2019 |
| Lambert Hire Limited | Administrative & support | 2017 |
| LAN TIN Foods Ltd | Hospitality | 2024 |
| Landhaul Developments Limited | Water & waste | 2019 |
| Landplanter Construction Limited | Construction | 2009 |
| Landplanter Limited | Real estate | 1985 |
| Landshaped Limited | Administrative & support | 2018 |
| Lansdale Civil Engineering Limited | Construction | 2026 |
| Larevolution Ltd | Wholesale & retail | 2020 |
| Larkrise Lowestoft (Suffolk) Ltd | Households | 2015 |
| Laura Bull Developments Ltd | Real estate | 2023 |
| Laurence Wright & Sons Limited | Agriculture & fishing | 1961 |
| Lawson Civil Engineering Limited | Construction | 2018 |
| Lawson Road Flats Limited | Households | 1985 |
| LBB Window Cleaning Ltd | Administrative & support | 2022 |
| LC Rope Access & Fabrication Ltd | Mining & quarrying | 2026 |
| LCB Technical Services Limited | Professional & scientific | 2021 |
| LCH Assistance Ltd | Extraterritorial | 2024 |
| LD Hammond Engineering Ltd | Professional & scientific | 2018 |
| Lead Wave Limited | Professional & scientific | 2022 |
| LEADMOUNTAIN3D Limited | Wholesale & retail | 2025 |
| Leather Refresh Ltd. | Other services | 2004 |
| Lecbo Group Ltd | Real estate | 2025 |
| LEE & Laura Caldwell Contractors Limited | Mining & quarrying | 2017 |
| LEE Pullum Enterprises Limited | Financial services | 2005 |
| Leesemay Limited | Health & social care | 2023 |
| Legacy Logistics Suffolk Limited | Transport & logistics | 2024 |
| Legal Decent Honest Truthful Limited | Administrative & support | 2010 |
| Leggett’S Printing Co. Ltd | Manufacturing | 2025 |
| Lentil Lettings Ltd | Real estate | 2022 |
| LES Dawson Consulting Limited | Professional & scientific | 2015 |
| Let's Future Calm Ltd | Professional & scientific | 2025 |
| Let's Go Essex Ltd | Hospitality | 2022 |
| Lets Check Ltd | Households | 2019 |
| Lewis Charles Investments Limited | Financial services | 2023 |
| Lewis Charles Rentals Limited | Real estate | 2020 |