| Kosmec Limited | Construction | 2025 |
| KP Fried Chicken Ltd | Hospitality | 2025 |
| Kristofer Anthony Brooks Ltd | Extraterritorial | 2024 |
| Krns Limited | Professional & scientific | 2006 |
| Krocstar Solutions Limited | Other services | 2019 |
| KS Property Group Ltd | Real estate | 2026 |
| KT Pumps Ltd | Water & waste | 2026 |
| Kuso Oishii Ltd | Wholesale & retail | 2023 |
| Kybird Developments Ltd | Construction | 2024 |
| L Creations Limited | Arts & recreation | 2024 |
| L M C Partnership Limited | Professional & scientific | 2002 |
| L&L Lloyd-Owen Ltd | Information & communication | 2025 |
| L. Harley Ltd | Professional & scientific | 2021 |
| LA Mama Restaurant Limited | Hospitality | 2015 |
| Lab-Med Limited | Manufacturing | 2001 |
| Laci Ltd | Manufacturing | 2020 |
| Ladin Takeaway Limited | Hospitality | 2026 |
| Laine Engineering (Feltwell) Limited | Manufacturing | 1967 |
| Laksha Limited | Hospitality | 2016 |
| Larchy Ltd | Wholesale & retail | 2025 |
| Latham's Restorations Ltd | Wholesale & retail | 2022 |
| Laurel Dairy Construction Limited | Construction | 2021 |
| Laurel Dairy Properties Limited | Construction | 2021 |
| Lausons Ltd | Extraterritorial | 2014 |
| Lausons Properties Ltd | Real estate | 2021 |
| Lavender Court (Northwold) Management Company Limited | Households | 2013 |
| Lazy Landscapes Ltd | Administrative & support | 2013 |
| LBC Mentoring Ltd | Administrative & support | 2023 |
| LCD Medical Ltd | Health & social care | 2023 |
| Leach Consulting & Associates Ltd | Professional & scientific | 2013 |
| Leadership Resource Initiative Ltd | Professional & scientific | 2022 |
| Leadsearch Limited | Administrative & support | 2007 |
| Lean Insight Limited | Professional & scientific | 2025 |
| Leaping Hare CIC | Wholesale & retail | 2010 |
| Leckytek Ltd | Manufacturing | 2019 |
| LEE Eastell Engineering Services Ltd | Professional & scientific | 2014 |
| LEE Inns Contract Solutions Limited | Manufacturing | 2022 |
| LEO MAX Limited | Wholesale & retail | 2001 |
| LET Britain Global Limited | Real estate | 2015 |
| LET Britain Limited | Extraterritorial | 2016 |
| Letton Road Nurseries Limited | Agriculture & fishing | 2001 |
| Libelula Ltd | Wholesale & retail | 2003 |
| Lifeshifter Coaching Ltd | Professional & scientific | 2023 |
| Lightwater Property Management Limited | Administrative & support | 2003 |
| LIL Gary's Plaice Limited | Hospitality | 2005 |
| Lime Hand Carwash Ltd | Administrative & support | 2026 |
| Linecircle Ltd | Arts & recreation | 2025 |
| Lingerie Master Ltd | Professional & scientific | 2026 |
| Linked Maintenance Limited | Construction | 2023 |
| Linkt D&G Ltd | Transport & logistics | 2025 |
| Little Eriswell Limited | Construction | 2014 |
| Little House on the Faerie Ltd | Wholesale & retail | 2025 |
| Little Norfolk Moving Company Ltd | Transport & logistics | 2026 |
| LIVE4LESS Ltd | Wholesale & retail | 2025 |
| Ljfconnected Ltd | Information & communication | 2014 |
| LJH Scott Properties Ltd | Real estate | 2025 |
| LKN Close Ltd | Hospitality | 2026 |
| Llamada UK Limited | Manufacturing | 2022 |
| LMW Property Ltd | Real estate | 2016 |
| Lochafield Heating Ltd | Construction | 2025 |
| Lodge Property Norfolk Ltd | Real estate | 2022 |
| Longleaf Ltd | Professional & scientific | 1972 |
| Lorna Soar Gallery Limited | Arts & recreation | 2003 |
| Lowden Construction Limited | Construction | 2011 |
| Lowden Developments Limited | Real estate | 2017 |
| Lowestoft Ice Company Limited | Wholesale & retail | 1960 |
| LT Clark Ltd | Hospitality | 2025 |
| LT Property Solutions Limited | Real estate | 2019 |
| LTN Groundworks Ltd | Construction | 2025 |
| Lukes Complete Property Services Limited | Construction | 2019 |
| Lulu Electrical Ltd | Construction | 2020 |
| Lumsden Grinders Limited | Wholesale & retail | 2002 |
| LVH Developments Ltd | Construction | 2022 |
| Lynce Ltd | Transport & logistics | 2017 |
| Lyons Studios Limited | Arts & recreation | 2024 |
| M Lawson & Sons Developments Ltd | Construction | 2024 |
| M Lawson & Sons Ltd | Real estate | 2020 |
| M S H Carpentry Services Ltd | Construction | 2022 |
| M Semmence Pubs Limited | Hospitality | 2024 |
| M&A Food Supplier Limited | Extraterritorial | 2022 |
| M&E Holdings (Suffolk) Limited | Professional & scientific | 2025 |
| M. Austin Limited | Administrative & support | 2001 |
| M. Klosinski Limited | Health & social care | 2021 |
| MAC Refrigeration Limited | Manufacturing | 2015 |
| Machined Precision Components Limited | Manufacturing | 2004 |
| MAD About Lawns Services Ltd | Other services | 2019 |
| MAH Legal Services Limited | Professional & scientific | 2017 |
| Maid Marion Way Management Company Limited | Households | 1991 |
| Mainway Group Ltd | Wholesale & retail | 2013 |
| Majestic Construction DBM Limited | Construction | 2018 |
| Mama D'S Homemade Cuisine and Catering Ltd | Hospitality | 2026 |
| Mama D’S Homemade Cuisine Limited | Hospitality | 2020 |
| Manista Properties Limited | Real estate | 2025 |
| Mannpower Electrical Services Limited | Construction | 1998 |
| Mansol Tech Limited | Manufacturing | 2018 |
| Mansol Technologies Limited | Manufacturing | 2015 |
| Manston Property and Estate Management Limited | Real estate | 2010 |
| Marketing by Consultants Ltd | Professional & scientific | 2026 |
| Marnick Landscapes Limited | Administrative & support | 2003 |
| Marston's Test Centre Ltd | Wholesale & retail | 2026 |