| Konrad Body Car Ltd | Wholesale & retail | 2019 |
| Konsument Ltd | Wholesale & retail | 2016 |
| Kookaburra Reader Limited | Manufacturing | 1988 |
| Kookaburra Sport Limited | Manufacturing | 1988 |
| Kori Construction (Holdings) Limited | Financial services | 2018 |
| Kori Construction Limited | Construction | 2009 |
| Kori Developments Limited | Financial services | 2025 |
| Kowal Ltd | Administrative & support | 2017 |
| Kpakaros Limited | Health & social care | 2013 |
| KPK Delivery Ltd | Wholesale & retail | 2020 |
| KR Bodywork Ltd | Wholesale & retail | 2025 |
| Krevive Limited | Health & social care | 2022 |
| Krevive Wellness Ltd | Other services | 2025 |
| Krolecs Vehicle Prep Ltd | Wholesale & retail | 2026 |
| Krona Financial Ltd | Professional & scientific | 2025 |
| KS Autodesign Ltd | Professional & scientific | 2025 |
| KS Clubs Ltd | Hospitality | 2024 |
| KSM Corp Limited | Wholesale & retail | 2025 |
| KSN Property Management Limited | Real estate | 2024 |
| Kszfinish Limited | Manufacturing | 2024 |
| Ktol Business Services Ltd | Professional & scientific | 2016 |
| Kudi Ltd | Transport & logistics | 2019 |
| Kudrat Ltd | Wholesale & retail | 2022 |
| Kwapisz Holdings Limited | Financial services | 2023 |
| Kyng Capital Limited | Real estate | 2022 |
| Kyng House Ltd | Real estate | 2024 |
| Kyonet-It Ltd | Information & communication | 2012 |
| L Adams Services Ltd | Transport & logistics | 2017 |
| L Stroncea Ltd | Wholesale & retail | 2023 |
| L Z Car Repair Ltd | Wholesale & retail | 2022 |
| L&S Signature Properties Limited | Real estate | 2021 |
| LA Fonte Bistro Ltd | Hospitality | 2025 |
| LA Fonte Corby Ltd | Hospitality | 2026 |
| Laboratory Expertise Innovation and Analysis Limited | Administrative & support | 2012 |
| Ladstock 56 Ltd | Households | 2017 |
| Laft Investment (Manchester) Ltd | Real estate | 2023 |
| Laft Investment Limited | Real estate | 2025 |
| Laion & M Ltd | Wholesale & retail | 2026 |
| Lakes Spice Bar Limited | Hospitality | 2022 |
| Lakeside Healthcare Limited | Professional & scientific | 2014 |
| Lakeview Cafe Corby Ltd | Hospitality | 2024 |
| Lakeviewcorby Ltd | Manufacturing | 2025 |
| Lamar Living Ltd | Hospitality | 2025 |
| Land Utilities Advisory Group Ltd | Real estate | 2022 |
| Landward Services Limited | Professional & scientific | 2004 |
| Lapatic Car Ltd | Wholesale & retail | 2024 |
| Larchmount Ltd | Real estate | 2013 |
| Latimer Ales Ltd | Manufacturing | 2012 |
| Latimer Fire Protection Limited | Public administration | 2013 |
| Latimer Paving Services Limited | Construction | 2019 |
| Laura's Nails Ltd | Other services | 2019 |
| Laurance Trans Ltd | Transport & logistics | 2017 |
| Laurence Falcatan Recruitment Limited | Administrative & support | 2023 |
| Laurence Recruitment Ltd | Administrative & support | 2012 |
| Lawson's of Corby Ltd | Transport & logistics | 2013 |
| Lazlo’S Car Body Shop Services Ltd | Wholesale & retail | 2024 |
| LB HGV Driver Ltd | Wholesale & retail | 2015 |
| LB Infra Limited | Construction | 2025 |
| LB Liquid Ltd | Hospitality | 2022 |
| Leadbitter Glass Ltd | Manufacturing | 2013 |
| Leadership in Action Limited | Professional & scientific | 2010 |
| Leading Lean Ltd | Professional & scientific | 2024 |
| Leading Staff Limited | Administrative & support | 2019 |
| Learnix Limited | Education | 2023 |
| Leave and Cleave Limited | Administrative & support | 2016 |
| Lechtaras Ltd | Wholesale & retail | 2026 |
| LEE Wright Project Management Limited | Construction | 2021 |
| Leea Logistics Ltd | Transport & logistics | 2025 |
| Leea Transport Ltd | Transport & logistics | 2024 |
| Leed Partner Limited | Professional & scientific | 2016 |
| Leighton Taylor Ltd | Administrative & support | 2009 |
| Leilany Transport Limited | Transport & logistics | 2024 |
| Leinto Plumbing Services Ltd | Construction | 2022 |
| Lemon Lime Ltd | Wholesale & retail | 2022 |
| LEN Manchester Motorcycles Limited | Wholesale & retail | 2021 |
| Lenek-Estate Ltd | Real estate | 2022 |
| Leobart Massage Ltd | Health & social care | 2014 |
| Leohan Ltd | Transport & logistics | 2024 |
| Leotrans Limited | Transport & logistics | 2016 |
| Leski Engineering Limited | Professional & scientific | 2023 |
| Let's Project Limited | Wholesale & retail | 2024 |
| Level UP Property Investment Ltd | Real estate | 2022 |
| Levi Care Providers Ltd | Health & social care | 2018 |
| Lewis Offshore Ltd | Professional & scientific | 2025 |
| LEX Talionis Ltd | Information & communication | 2021 |
| Lexent Law Chambers Ltd | Professional & scientific | 2026 |
| Lexiton Ltd | Other services | 2025 |
| LFC - Little FOX Courier Ltd | Transport & logistics | 2014 |
| LG James (LLV) Ltd | Real estate | 2016 |
| Lgjames Ltd | Real estate | 2015 |
| Lgjamesgroup Ltd | Real estate | 2026 |
| LGT Services Ltd | Health & social care | 2024 |
| LH Corby Limited | Hospitality | 2026 |
| Lhdriving Ltd | Transport & logistics | 2025 |
| Lheva Limited | Professional & scientific | 2025 |
| Liberty Outreach Chapel International Ltd | Other services | 2021 |
| Liblogic Ltd | Information & communication | 2019 |
| Life Care Technology UK Limited | Wholesale & retail | 2013 |
| Lifeline Mindcare Europe Limited | Education | 2017 |
| Light & Shade Solutions Limited | Wholesale & retail | 2018 |