| JOE Skipper Pro Triathlete Ltd | Arts & recreation | 2015 |
| John Collins Ltd | Information & communication | 2005 |
| John Harvey Engineering Limited | Manufacturing | 1985 |
| John Hutton Butchers Ltd | Wholesale & retail | 2014 |
| John Ives Ltd | Wholesale & retail | 2007 |
| John Pilgrim Limited | Other services | 2017 |
| Jointblock Residents Management Limited | Other services | 1987 |
| JON Lloyd Limited | Information & communication | 2005 |
| Jonathan Pascoe Pratt Ltd | Wholesale & retail | 2006 |
| Jones & Brotherton Plumbing & Heating Limited | Construction | 2015 |
| Jools Faiers Graphic Designers Limited | Information & communication | 2012 |
| Jovern Ltd | Wholesale & retail | 2023 |
| JP Quigley Limited | Wholesale & retail | 2007 |
| JPB Social Work Ltd | Professional & scientific | 2019 |
| JPH Anglian Services Limited | Administrative & support | 2011 |
| Jptproducts Ltd | Wholesale & retail | 2024 |
| JRB Carpentry & Joinery Ltd | Construction | 2026 |
| JRB Rail Solutions Ltd | Construction | 2021 |
| JRB Roofing & Construction Ltd | Construction | 2025 |
| JS Global Ltd | Professional & scientific | 2018 |
| JS Killen Ltd | Other services | 2022 |
| JT Pigs Ltd | Agriculture & fishing | 2024 |
| Julian Marshall Ltd | Arts & recreation | 2007 |
| Juniper Studio Limited | Information & communication | 2021 |
| Jurston Owners Trustee Limited | Financial services | 2023 |
| Just ADD NIC Ltd | Wholesale & retail | 2018 |
| Just Firewood Ltd | Agriculture & fishing | 2019 |
| Just Tiles Importers Ltd | Wholesale & retail | 2017 |
| Just Tiles Suffolk Ltd | Wholesale & retail | 2013 |
| JUST42 | Health & social care | 2002 |
| Juto Developments Ltd | Real estate | 2022 |
| JW Logistics & Warehousing Ltd | Transport & logistics | 2019 |
| JWT Enterprises Ltd | Professional & scientific | 2023 |
| K Baines Limited | Real estate | 2006 |
| K Towler Ltd | Construction | 2018 |
| Kabd Ltd | Professional & scientific | 2009 |
| Kabogoza Business Logistics Ltd | Transport & logistics | 2019 |
| Kap-Uk Ltd | Wholesale & retail | 2016 |
| Karus Consult Limited | Construction | 2016 |
| Katie Kemball Limited | Extraterritorial | 2020 |
| Katie's Garden Ltd | Wholesale & retail | 2026 |
| KBR Building Services Ltd | Manufacturing | 2025 |
| KCE Safety Services Ltd | Professional & scientific | 2022 |
| KCP Media Limited | Professional & scientific | 2024 |
| Kdmoss Ltd | Administrative & support | 2013 |
| Keaton Enterprises Limited | Professional & scientific | 2025 |
| Keep Communications Ltd | Professional & scientific | 2018 |
| Keko Estates Limited | Real estate | 2025 |
| Kensal Associates Ltd | Professional & scientific | 2018 |
| Ker-Way Building and Groundworks Limited | Construction | 2010 |
| Keus Services Ltd | Professional & scientific | 2024 |
| Keys Removals Limited | Transport & logistics | 2019 |
| KF East Anglia Ltd | Real estate | 2025 |
| Kidd Farm Machinery Limited | Wholesale & retail | 2023 |
| KIM Meredew (Stone Studio) Ltd. | Manufacturing | 2012 |
| Kindred Generation Limited | Energy | 2011 |
| Kindwater Limited | Construction | 2001 |
| Kings Hill Community Limited | Households | 2017 |
| Kingston Farm Enterprises Limited | Real estate | 2022 |
| Kingston Farm Projects Limited | Real estate | 2023 |
| Kinsellas Hair Limited | Other services | 2013 |
| Kirby Villas West Limited | Administrative & support | 2013 |
| Kirkpatrick Health Limited | Health & social care | 2026 |
| KIT Car Finder Limited | Information & communication | 2008 |
| Kiwi's Bike Shop Ltd | Wholesale & retail | 2021 |
| Kojak Holdings Limited | Wholesale & retail | 2023 |
| KOO KOO Hair Design Limited | Other services | 2003 |
| KP Glass Fibre and Plastering Ltd | Construction | 2006 |
| Kpbailey Property Limited | Hospitality | 2025 |
| KPM Vehicle Maintenance and Sales Ltd | Wholesale & retail | 2002 |
| Krimira Ltd | Hospitality | 2021 |
| KUY & Co Flowers Limited | Wholesale & retail | 2024 |
| Kyro App Ltd | Information & communication | 2026 |
| Kysonview Ltd | Professional & scientific | 2024 |
| L & N Tennant Limited | Arts & recreation | 2013 |
| L J Brand Builders Limited | Construction | 2019 |
| L J C Building Services Ltd | Construction | 2002 |
| L.E. Toshi Limited | Agriculture & fishing | 1975 |
| L.E.Tuckwell Limited | Agriculture & fishing | 1958 |
| LA Llama Ltd | Wholesale & retail | 2016 |
| Labelvaults Limited | Wholesale & retail | 2026 |
| Lakebootstrap Limited | Professional & scientific | 2023 |
| LAN RUI Limited | Education | 2021 |
| Lancelink Ltd | Information & communication | 2025 |
| Lanchester Holdings Limited | Financial services | 2025 |
| Land Group (Breckland) Limited | Construction | 2015 |
| Land Group (Ports) LLP | | 2010 |
| Land Group Properties Limited | Real estate | 2020 |
| Land Property Holdings Limited | Real estate | 2003 |
| Land Property Nominees Limited | Administrative & support | 2006 |
| Landypart UK Limited | Wholesale & retail | 2008 |
| LAO ZI Limited | Health & social care | 2013 |
| Larchfield Properties Limited | Real estate | 1988 |
| Lark Interiors Limited | Professional & scientific | 2021 |
| Larsen Consultancy Ltd | Administrative & support | 2020 |
| Laser Patterns Limited | Manufacturing | 2002 |
| Last Minute Eats Limited | Information & communication | 2025 |
| Laura Jane Boutique Limited | Wholesale & retail | 2011 |
| Lavelle Design & Consulting Ltd | Professional & scientific | 2023 |
| Lawford House Limited | Construction | 2014 |