| Keepa Limited | Arts & recreation | 2026 |
| Kenai Logistics Ltd | Financial services | 2020 |
| Kenai Training Ltd | Education | 2019 |
| Kent RGN Ltd | Health & social care | 2021 |
| Kentford Farm Stud Limited | Agriculture & fishing | 2003 |
| Kenya Grace Limited | Information & communication | 2025 |
| Kerry Plant and Transport Limited | Construction | 1993 |
| Ketterix Solutions Ltd | Information & communication | 2026 |
| Kewans Limited | Professional & scientific | 2017 |
| Key Holdings (Southern) Limited | Financial services | 2022 |
| KG Communications Limited | Professional & scientific | 2025 |
| KGJ Music Ltd | Information & communication | 2023 |
| KGJ Touring LLP | | 2024 |
| Kgtr Ltd | Professional & scientific | 2024 |
| KHE Partnership LLP | | 2009 |
| Kidz Play (UK) Limited | Education | 2008 |
| Kievel GAS Limited | Construction | 2012 |
| Kimbridge Trout Fishing Limited | Agriculture & fishing | 2022 |
| Kimm Investment Limited | Extraterritorial | 2025 |
| Kimm Services Limited | Health & social care | 2025 |
| KIN Barber Limite Limited | Other services | 2026 |
| KIN Barbers Limited | Other services | 2020 |
| Kinetics Ltd | Professional & scientific | 1998 |
| King John's House and Tudor Cottage Trust Limited (the) | Arts & recreation | 1979 |
| Kings Worthy Garage Ltd | Wholesale & retail | 2018 |
| Kingsmead Residents (Wellow) Ltd. | Professional & scientific | 1990 |
| Kingsworthy Early Years Centre Limited | Education | 2021 |
| Kiran Estates Ltd | Real estate | 2024 |
| Kirkpace Limited | Manufacturing | 1981 |
| KIT and Caboodle Trading Ltd. | Wholesale & retail | 2008 |
| Kitchen Link Ltd | Wholesale & retail | 2023 |
| Kitchens Collection Limited | Wholesale & retail | 2001 |
| Kite Orthopaedics Ltd | Health & social care | 2020 |
| Klesa Limited | Professional & scientific | 2012 |
| KN Media Limited | Professional & scientific | 2010 |
| Knightsway Homes Limited | Construction | 2008 |
| Knightwood Estates Limited | Real estate | 1999 |
| Knotweed Control Ltd | Administrative & support | 2013 |
| Kojak Constructions Limited | Construction | 2022 |
| Kooner Medical Services Limited | Health & social care | 2019 |
| Kotecha Cardiology Limited | Real estate | 2021 |
| Kotecha Properties Limited | Real estate | 2026 |
| KT Decorating Limited | Construction | 2019 |
| Ktime Limited | Information & communication | 2023 |
| Kumar Associates Limited | Professional & scientific | 2007 |
| Kumon Southampton Shirley Ltd | Education | 2019 |
| KVM E.N.T. Services Limited | Health & social care | 2023 |
| L a Carpentry & Construction Ltd | Construction | 2018 |
| L and J Matthews Ltd | Health & social care | 2024 |
| L Baker Consulting Ltd | Financial services | 2012 |
| L C Russell Ltd | Manufacturing | 2024 |
| L E Fabrications Limited | Professional & scientific | 2008 |
| L R Metalworks Limited | Manufacturing | 2023 |
| L S Fencing Limited | Construction | 2020 |
| L S R Medical Limited | Health & social care | 2014 |
| L. FEE Limited | Other services | 2001 |
| Lagad Vision Laboratory Ltd | Manufacturing | 2008 |
| Lahalford Ltd | Information & communication | 2022 |
| Lake Carpathia Ltd | Agriculture & fishing | 2015 |
| Lakewood Developments Limited | Construction | 2009 |
| LAN(950) Limited | Real estate | 2022 |
| Lancaster Close (Bromley) Management Co. Limited | Households | 1965 |
| Lancer Property Holdings Limited | Real estate | 2006 |
| Landbrook Ltd | Real estate | 2019 |
| Landford Homes and Developments Ltd | Real estate | 2025 |
| Landford Self Storage Limited | Transport & logistics | 2015 |
| Landguard Nexus Limited | Manufacturing | 2021 |
| Landguard Systems Limited | Manufacturing | 2006 |
| Landmark Holdings Portsmouth Limited | Financial services | 2024 |
| Landshape Ltd | Professional & scientific | 2009 |
| Landspeed Affordable Homes Limited | Construction | 2001 |
| Landspeed Development Consultancy Limited | Construction | 2011 |
| Landspeed Homes Limited | Construction | 2013 |
| Landspeed Limited | Construction | 2012 |
| Lansdowne Nursery Estate Limited | Households | 1963 |
| Laura Fisher Ltd | Wholesale & retail | 2022 |
| Lauren Hill Hairdressing Ltd | Other services | 2020 |
| Lavender Gate Services Ltd. | Other services | 2003 |
| Lawnsolve Ltd | Administrative & support | 2026 |
| Lawson Jewellers Limited | Wholesale & retail | 2009 |
| LC Carpentry and Joinery Limited | Manufacturing | 2023 |
| LDR Commercial Services Ltd | Professional & scientific | 2017 |
| LE Jardinier Limited | Administrative & support | 2010 |
| Leafy Tree Surgeons Ltd | Agriculture & fishing | 2023 |
| Leaguecity Limited | Real estate | 1990 |
| Lece Ltd | Professional & scientific | 2022 |
| Lees Consulting Services Limited | Professional & scientific | 2016 |
| Legal Briefs Limited | Professional & scientific | 2020 |
| Leisure Staff Ltd | Administrative & support | 2011 |
| Lemieux Limited | Administrative & support | 2003 |
| Lemon and Jinja Ltd | Wholesale & retail | 2021 |
| Leon 82 Ltd | Professional & scientific | 2018 |
| Leslie Hitchcock House & John Miller House RTM Company Ltd | Households | 2021 |
| LET Manager Limited | Real estate | 2019 |
| Level Access Lifts Ltd | Manufacturing | 2006 |
| Level Group Holdings Ltd | Financial services | 2019 |
| Level Lift Services Ltd | Other services | 2019 |
| Lewis and Irene Limited | Professional & scientific | 2013 |
| LEX Real Estate Limited | Real estate | 2021 |
| Lexican Investments Ltd | Professional & scientific | 2023 |