| Konnect Contractors Limited | Construction | 2024 |
| Konrad Marine Ltd | Other services | 2019 |
| Koor Associates Ltd | Professional & scientific | 2023 |
| Koraf Group Holdings Ltd | Hospitality | 2016 |
| Koya Shawarma Limited | Hospitality | 2026 |
| KP & Co Properties Ltd | Real estate | 2020 |
| KPG Carpentry Limited | Construction | 2023 |
| KR Automotive Finishing Ltd | Wholesale & retail | 2026 |
| KR Property Solutions Ltd | Administrative & support | 2005 |
| Kraven Inc Limited | Wholesale & retail | 2025 |
| Kresha Limited | Hospitality | 2024 |
| KRF Plastering Ltd | Construction | 2018 |
| Kristallklar Communications Limited | Information & communication | 2010 |
| KRK Focus Consulting Limited | Professional & scientific | 2021 |
| Krsurfacing Ltd | Construction | 2019 |
| Krupski Ltd | Construction | 2019 |
| Krytonite App Company Limited | Information & communication | 2025 |
| KS Property Holdings Limited | Real estate | 2006 |
| Kskc Holdings Ltd | Financial services | 2025 |
| Kskc Ltd | Professional & scientific | 2024 |
| KSM Projects Ltd | Construction | 2024 |
| Ktkbb Properties Portsmouth Limited | Real estate | 2025 |
| KTL Europe (UK) Ltd | Transport & logistics | 2019 |
| Kubala Construction Ltd | Construction | 2022 |
| Kudos Living Ltd | Real estate | 2017 |
| Kudos People Limited | Administrative & support | 2009 |
| Kullars Ltd | Financial services | 2016 |
| Kupis Property Ltd | Real estate | 2021 |
| Kuranda Special Situations Limited | Professional & scientific | 2024 |
| Kurdish Line Limited | Other services | 2024 |
| Kurdistan Butcher Portsmouth Ltd | Wholesale & retail | 2023 |
| Kuru Hair & Beauty Ltd | Other services | 2021 |
| Kusinako Atbp Ltd | Hospitality | 2022 |
| Kyakos Limited | Real estate | 2024 |
| Kyle Smith Game Company Limited | Information & communication | 2023 |
| Kznk Limited | Construction | 2023 |
| L & C Williams Limited | Construction | 2010 |
| L & P Consultancy Ltd | Professional & scientific | 2014 |
| L & R Estates Limited | Real estate | 2019 |
| L / J Mechanical and Electrical Limited | Construction | 2023 |
| L a Garden Services Ltd. | Administrative & support | 2013 |
| L and J Premier Properties Ltd | Real estate | 2018 |
| L D Beves Decor Ltd | Construction | 2008 |
| L Daniels Consultancy Limited | Administrative & support | 2012 |
| L Gess Leisure Limited | Hospitality | 2017 |
| L Knight Plastering Limited | Construction | 2022 |
| L M D Utilities Ltd | Construction | 2025 |
| L M Electrics [Southern] Limited | Construction | 2002 |
| L R Blakers Electrical Limited | Construction | 2017 |
| L&A Decor Southern Ltd | Construction | 2022 |
| L&A Van Centre Ltd | Wholesale & retail | 2026 |
| L&C Traffic Management Ltd | Construction | 2022 |
| L&D DRY Lining Ltd | Construction | 2018 |
| L&J Rides Ltd | Arts & recreation | 2024 |
| L.A Domestic Cleaning Ltd | Administrative & support | 2019 |
| L.C.Webb & Son(Builders)Limited | Households | 1951 |
| L.D.Utilities Limited | Construction | 2020 |
| L.Dubisson Plumbing and Heating Ltd | Construction | 2022 |
| L.Duff Psychotherapist Ltd | Health & social care | 2024 |
| L.E-Electrical (South) Ltd | Construction | 2017 |
| L.O.J Holdings Limited | Financial services | 2020 |
| L.S Vending Ltd | Wholesale & retail | 2024 |
| L2 Decor Ltd | Construction | 2025 |
| LA Espanola Limited | Hospitality | 2005 |
| LA Veggie Ltd | Hospitality | 2022 |
| LAB Training Limited | Other services | 2015 |
| Lab-Bubble Limited | Extraterritorial | 2012 |
| Laburnum Glass Limited | Construction | 2018 |
| Laceby (G) Limited | Hospitality | 2016 |
| Ladnxaeer Analytics Ltd | Professional & scientific | 2025 |
| Lady Land Lady Ltd | Hospitality | 2024 |
| Ladya Ltd | Wholesale & retail | 2003 |
| LAG & Clad Ltd | Professional & scientific | 2022 |
| Laguna Studios Limited | Information & communication | 2024 |
| Laine LEX Properties Ltd | Real estate | 2016 |
| Lair Share Ltd | Real estate | 2019 |
| Laithan Consultants Ltd | Professional & scientific | 2022 |
| Lake Farm Riding Limited | Arts & recreation | 2023 |
| Lakeside Pallets Limited | Manufacturing | 2017 |
| Lala Barbers Ltd | Other services | 2019 |
| Lala Barbers Portsmouth Ltd | Other services | 2021 |
| Lala Brothers Ltd | Wholesale & retail | 2024 |
| Lalila LP | | 2021 |
| Lambournes Property Holdings Limited | Financial services | 2015 |
| Lambournes Surveyors Limited | Other services | 1996 |
| Laminin Solutions Limited | Information & communication | 2009 |
| Lamonbys Limited | Construction | 2010 |
| Lampard Design Limited | Professional & scientific | 2018 |
| Land Soil Water Management Ltd | Administrative & support | 2024 |
| Landing PAD Limited | Professional & scientific | 2006 |
| Landscape by Design London Ltd | Administrative & support | 2023 |
| Lang Wilson Electrical Limited | Construction | 2023 |
| Langford Building Ltd | Other services | 2014 |
| Langford Strategic Limited | Professional & scientific | 1999 |
| Langley Demolition Limited | Administrative & support | 2000 |
| Langstone Brook Management Company Limited | Households | 2006 |
| Langstone Consulting (Havant) Limited | Information & communication | 2012 |
| Langstone Court Management Company Limited | Real estate | 2007 |
| Langstone GAS Ltd | Construction | 2021 |
| Langstone Lettings & Management Ltd | Real estate | 2017 |