| Kiming Flats Limited | Households | 2026 |
| Kingfisher House Management Company Limited | Real estate | 1996 |
| Kingsend Ruislip (Number 30) Management Company Limited | Households | 2007 |
| Kiren Passi Ltd | Professional & scientific | 2020 |
| Kirk Development Management Ltd | Professional & scientific | 2015 |
| Kirk Real Estate Ltd | Construction | 2016 |
| Kitsbury Advisors Limited | Professional & scientific | 2023 |
| Klein Aviation Services Limited | Transport & logistics | 2021 |
| Klondyke House Freehold Company Limited | Real estate | 2009 |
| Klondyke Management Limited | Households | 2007 |
| KM Residents Management Company Ltd | Households | 2020 |
| KMK Capital Limited | Financial services | 2021 |
| Knapsack Media Ltd | Information & communication | 1993 |
| Knoll Properties Limited | Construction | 1980 |
| Knowledge Hemispheres Limited | Professional & scientific | 2001 |
| Korden Holdings Limited | Real estate | 2024 |
| KPF Productions Limited | Information & communication | 2026 |
| Kraj Incorporated Limited | Professional & scientific | 2009 |
| Kristina Pulejkova Studio Limited | Arts & recreation | 2025 |
| KRS Consulting Services Limited | Professional & scientific | 2017 |
| KSP Holdings Ltd | Construction | 2018 |
| Ktlnb Ltd | Education | 2021 |
| Kuro KIN Limited | Information & communication | 2016 |
| Kyan Clinic Limited | Health & social care | 2019 |
| Kylebuyandsell Limited | Wholesale & retail | 2025 |
| Kylieharveydesign Ltd | Wholesale & retail | 2018 |
| L & M Spares Limited | Wholesale & retail | 2009 |
| L'Era Jewellery Ltd | Wholesale & retail | 2022 |
| LA Bodega Tapas Limited | Hospitality | 1999 |
| LA Cantina (Marlow) Ltd | Hospitality | 2010 |
| LA Piccola Deli Holland Park Ltd | Hospitality | 2013 |
| LA Piccola Deli Limited | Wholesale & retail | 2011 |
| LA Piccola Deli Retail Holdings Limited | Financial services | 2015 |
| LA Piccola Dely Limited | Hospitality | 2007 |
| Labwaste Ltd | Water & waste | 2005 |
| Ladbroke Close (Woodley) Management Limited | Households | 2006 |
| Laison Consulting Limited | Financial services | 2022 |
| Lama Advisory Limited | Professional & scientific | 2022 |
| Lambourne Court Residents Company Limited | Professional & scientific | 2000 |
| Lancastria Mews Residents Limited | Households | 1988 |
| Land Graham Partnership LLP | | 2007 |
| Landcroft Limited | Real estate | 1992 |
| Landis Media Ltd | Information & communication | 2006 |
| Langston Court Residents Association Limited | Households | 1991 |
| Langton Communications Limited | Professional & scientific | 2025 |
| Lansview Group Holdings Ltd | Construction | 2017 |
| Lansview Homes (7 Woodgrange) Limited | Construction | 2021 |
| Lansview Homes (Woodgrange) Limited | Real estate | 2021 |
| Lapsed Pedals Ltd | Real estate | 2022 |
| Lateral Translation Limited Liability Partnership | | 2008 |
| Laurelvale House Ltd | Households | 2017 |
| Laurent-Perrier (UK) Limited | Wholesale & retail | 1978 |
| Lcms Trading Limited | Wholesale & retail | 2023 |
| LCP II Bidco Limited | Financial services | 2026 |
| LCP II Limited | Financial services | 2026 |
| LCP II Midco Limited | Financial services | 2026 |
| Leaders Farm Stud Ltd | Agriculture & fishing | 2023 |
| Leadership Intelligence (LQ) Limited | Professional & scientific | 2017 |
| Learn and Lead Limited | Professional & scientific | 2020 |
| Lebeau & Co Ltd | Real estate | 2005 |
| Lectern Engineering Limited | Manufacturing | 1987 |
| LEE & Co Ltd | Professional & scientific | 2014 |
| Legacy Education Alliance International Ltd | Education | 2001 |
| Leighton Fine Art Limited | Wholesale & retail | 2012 |
| Lenton & Associates Limited | Professional & scientific | 2010 |
| Lenton Transport Ltd | Professional & scientific | 2016 |
| Leoville Limited | Real estate | 1997 |
| Lester Lane Limited | Professional & scientific | 2020 |
| Let's Move IT Ltd | Transport & logistics | 2020 |
| Leviathan Commerce Limited | Manufacturing | 2024 |
| Levity Ltd | Professional & scientific | 2023 |
| Lexeron Consulting Limited | Information & communication | 2024 |
| LFA (EOT) Limited | Professional & scientific | 2023 |
| Life Science Business Consulting Limited | Professional & scientific | 2016 |
| Life Science Business Solutions Limited | Professional & scientific | 2010 |
| Light Spark Group Limited | Information & communication | 2023 |
| Lightray Consulting Limited | Information & communication | 2008 |
| Lila and Lion Ltd | Wholesale & retail | 2020 |
| Lily & Bean Limited | Manufacturing | 2016 |
| Lily Riley Design Limited | Professional & scientific | 2024 |
| Liminal Sustainability Limited | Professional & scientific | 2026 |
| Link Trim Limited | Manufacturing | 2012 |
| Linkside Maidenhead Limited | Households | 2008 |
| Linktra Technology Limited | Information & communication | 1998 |
| Linux Foundation UK Limited | Information & communication | 2022 |
| Lion House (Manorbier) Management Limited | Real estate | 2014 |
| Liongate Capital Partners Limited | Professional & scientific | 2025 |
| Liston House RTM Company Limited | Households | 2019 |
| Liston Solutions Limited | Information & communication | 2019 |
| Lite Prop Ltd | Real estate | 2018 |
| Little Marlow Landscapes Ltd | Wholesale & retail | 2016 |
| Little Stone Mews Residents Limited | Households | 2014 |
| Living Streams Consultancy (UK) Limited | Professional & scientific | 2005 |
| Living Tennis Ltd | Education | 2011 |
| LJ Marketing Services Ltd | Professional & scientific | 2018 |
| LJO CK Limited | Wholesale & retail | 2023 |
| LKW Medical Limited | Health & social care | 2016 |
| Lloyds Tobacco Company Limited | Extraterritorial | 1994 |
| LM Assets Limited | Professional & scientific | 2014 |
| LNT Commercial Cleaning Services Ltd | Administrative & support | 2016 |