| Kletzien Projects & Solutions Limited | Construction | 2015 |
| KLF Insurance Brokers Limited | Financial services | 2003 |
| Klixs Trans Ltd | Transport & logistics | 2019 |
| Klmh Limited | Real estate | 2015 |
| KLO Photography & Equine Limited | Agriculture & fishing | 2026 |
| KLO Technical Services Limited | Professional & scientific | 2024 |
| KLV Investments Ltd | Financial services | 2014 |
| KM Griffiths Ltd | Professional & scientific | 2025 |
| Kmar Properties Limited | Real estate | 2000 |
| Kmfdistributons Ltd | Wholesale & retail | 2026 |
| KMT Enterprises Limited | Real estate | 2019 |
| Knaptoft Hall Farm Limited | Agriculture & fishing | 1999 |
| Knead Massage Ltd | Information & communication | 2025 |
| Kneeton Grove (East Bridgford) Residents Management Company Limited | Households | 2025 |
| Knight Hawk Capital Ltd | Financial services | 2025 |
| Knight Properties (Halifax) Limited | Hospitality | 2014 |
| Knight Properties (Shrewsbury) Limited | Hospitality | 2014 |
| Knight Taverns Ltd | Hospitality | 2025 |
| Knights Court (Rothley) Management Limited | Households | 2007 |
| Knights Meadow Management Company Limited | Real estate | 2022 |
| Knights Tailoring Ltd | Other services | 2009 |
| KNO Ltd | Education | 2013 |
| KNO Solutions Limited | Education | 2020 |
| Knot & Grain Oak Limited | Wholesale & retail | 2026 |
| Koate Limited | Manufacturing | 2020 |
| Kolal Ltd | Wholesale & retail | 2023 |
| Kooner Supermarket Ltd | Wholesale & retail | 2012 |
| Kordis Limited | Administrative & support | 2002 |
| KP Morley Management Company Limited | Households | 2023 |
| KP1320 Limited | Information & communication | 2015 |
| KQD Limited | Professional & scientific | 2020 |
| KR RAD Services Ltd | Health & social care | 2025 |
| Krandall Legal Services Limited | Professional & scientific | 2022 |
| KRW Consulting Ltd | Professional & scientific | 2026 |
| KS Top Consulting Limited | Professional & scientific | 2025 |
| KSJ Medical Ltd | Health & social care | 2021 |
| KTD Property (PVT) Ltd | Real estate | 2020 |
| KTWENTY2 Limited | Construction | 2013 |
| KUB Limited | Professional & scientific | 1996 |
| Kube Care Consultancy Limited | Professional & scientific | 2024 |
| Kube Property Investments Ltd | Real estate | 2021 |
| Kudu Construct Ltd | Construction | 2023 |
| Kurdish KB Barbers Ltd | Other services | 2023 |
| Kurekure Solutions Ltd | Information & communication | 2022 |
| Kvart Shopping Ltd | Wholesale & retail | 2025 |
| KW Contracting Ltd | Manufacturing | 2021 |
| KW Property Maintenance Limited | Construction | 2024 |
| Kyles Home C.I.C. | Other services | 2022 |
| Kynaston Luxe Safari Tents Ltd | Hospitality | 2026 |
| L & C Employment Consulting Limited | Administrative & support | 2017 |
| L Capital Limited | Financial services | 2026 |
| L E Speed Limited | Professional & scientific | 2021 |
| L E Tyres Ltd | Wholesale & retail | 2024 |
| L Evans & SON Groundworks Ltd | Construction | 2024 |
| L Fest CIC | Arts & recreation | 2011 |
| L J F Conveyor Hub Limited | Professional & scientific | 2018 |
| L J Hannah Occupational Health Ltd | Professional & scientific | 2014 |
| L Pugh & Co Ltd | Wholesale & retail | 2025 |
| L V R Limited | Professional & scientific | 2003 |
| L&C Services Ltd | Administrative & support | 2021 |
| L&P Property Development Limited | Real estate | 2018 |
| L&R Housing Ltd | Real estate | 2025 |
| L. E. Kean Ltd | Information & communication | 2019 |
| L.E.A. Autos Limited | Wholesale & retail | 2005 |
| L.G. Blower Specialist Bricklayer Limited | Construction | 2003 |
| LA Coupe Limited | Wholesale & retail | 2024 |
| LA Trattoria (Shrewsbury) Limited | Hospitality | 1996 |
| LA Triestina Ltd | Hospitality | 2013 |
| Labyrinth Management Limited | Professional & scientific | 1998 |
| Lacus Logistics UK Ltd | Transport & logistics | 2021 |
| Lady Forester Care Home Limited | Real estate | 2024 |
| Lakeside Classics Ltd | Wholesale & retail | 2015 |
| Lakeside Consultancy Ltd | Wholesale & retail | 2021 |
| Lakeside Mews (Birmingham) Management Company Limited | Households | 2001 |
| Lakeside Residents (Alton) Management Company Limited | Households | 2007 |
| Lakeside View Management Company Limited | Households | 2005 |
| Lamb Developments Limited | Real estate | 2019 |
| Lamba Art Ltd | Arts & recreation | 2022 |
| Lambda Networks Limited | Wholesale & retail | 2021 |
| Lambert Court Management (Leicester) Limited | Households | 1985 |
| Lambert LEE Limited | Professional & scientific | 2022 |
| Lambert Living Ltd | Wholesale & retail | 2020 |
| Lambert Noir Limited | Wholesale & retail | 2022 |
| Lambretta Concessionaires Ltd | Agriculture & fishing | 2017 |
| Laminate & PLY Ltd | Wholesale & retail | 2022 |
| Lammont Ltd | Wholesale & retail | 2024 |
| Lanah Limited | Financial services | 2016 |
| Lancaster Park (West Malling) Management Company Limited | Real estate | 2021 |
| Lancaster Square (Ilford) Management Company Limited | Households | 2005 |
| Lancegreen Limited | Households | 1984 |
| Lancroft Commercial Limited | Construction | 2011 |
| Lancroft Developments Limited | Construction | 1999 |
| Landona House Limited | Health & social care | 2004 |
| Landworthley Limited | Hospitality | 2025 |
| Landywood Snooker Club Limited | Arts & recreation | 2019 |
| Lange Productions Limited | Information & communication | 1999 |
| Langton Lodge (Wakefield) Management Company Limited | Real estate | 2022 |
| Lanyon Bowdler Developments LLP | | 2007 |
| Lanyon Bowdler LLP | | 2010 |
| Lanyon Bowdler Services Limited | Professional & scientific | 1990 |