| JW Estate Management Limited | Real estate | 2026 |
| JWF Partnership Ltd | Professional & scientific | 2021 |
| JZR Designs Limited | Wholesale & retail | 2019 |
| K & Morgan Limited | Administrative & support | 2017 |
| K D C Construction Ltd | Construction | 2015 |
| K.R.M Synergy Limited Liability Partnership | | 2025 |
| K3DSPACE Ltd | Manufacturing | 2025 |
| KA Handyman Services Limited | Administrative & support | 2013 |
| Kampaign Solutions Ltd | Professional & scientific | 2023 |
| Kanchi Technologies Limited | Information & communication | 2016 |
| Kandy Pear Tree Limited | Real estate | 2022 |
| Kasso Sienn Ltd | Wholesale & retail | 2026 |
| Katie Abbotts Communications Ltd. | Professional & scientific | 2013 |
| Katie L Thatcher Beauty Ltd | Other services | 2025 |
| Kayakomat Limited | Administrative & support | 2024 |
| Kbmx Ltd | Information & communication | 2024 |
| Kdls Services Limited | Professional & scientific | 2024 |
| KE Scott Consulting Limited | Professional & scientific | 2021 |
| Keay Homes (Windrush) Limited | Extraterritorial | 2012 |
| Kefla UK Ltd. | Wholesale & retail | 2021 |
| Kemp Plant Limited | Administrative & support | 2009 |
| Kerb 'N' Turf Limited | Wholesale & retail | 2009 |
| Keto Engineering Limited | Manufacturing | 2018 |
| Keyes Farms Ltd | Agriculture & fishing | 2011 |
| KGK Service Ltd | Professional & scientific | 2024 |
| Khaya Developments Ltd | Real estate | 2022 |
| Kick Asset Finance Limited | Financial services | 2019 |
| Kieva Ltd | Information & communication | 2019 |
| KILBURN4LIFE Ltd | Public administration | 2022 |
| Killoran Demolition Ltd | Construction | 2018 |
| Kilmartin Castle Limited | Hospitality | 2023 |
| Kilmaurs Design Ltd | Professional & scientific | 2011 |
| Kilzer Ltd | Arts & recreation | 2023 |
| King Roofing Buckingham Ltd | Construction | 2017 |
| Kingdom Solutions Limited | Professional & scientific | 2020 |
| Kingwood Project Management Ltd | Construction | 2021 |
| Kiri & Daraboth Enterprise Ltd | Financial services | 2024 |
| Kirtech System Solutions Limited | Professional & scientific | 2007 |
| Kitchen and Catering Services Ltd | Hospitality | 2023 |
| Kitchen Catering ENG Ltd | Hospitality | 2026 |
| KK Consulting (Lovell) Limited | Professional & scientific | 2015 |
| KL Rail Operations and Projects Management Ltd | Administrative & support | 2018 |
| Klavyn Digital Ltd | Information & communication | 2025 |
| KLE Plastics & Recycling Limited | Manufacturing | 1987 |
| KLK Consulting Limited | Information & communication | 2026 |
| Knoll UK Limited | Wholesale & retail | 1999 |
| Koineden Limited | Financial services | 2024 |
| KPJ Consultancy Limited | Professional & scientific | 2024 |
| KR Performance Ltd | Wholesale & retail | 2025 |
| KR Sport Limited | Arts & recreation | 2011 |
| Krisba Limited | Wholesale & retail | 2024 |
| Kritikal Solutions Limited | Information & communication | 2013 |
| KRM Projects Limited | Administrative & support | 2026 |
| Krypa Medical Care Ltd | Health & social care | 2013 |
| KS Decor Limited | Construction | 2013 |
| Kthalm UK Limited | Real estate | 2024 |
| Kudil Homes Ltd | Real estate | 2020 |
| Kynance Cottage Ltd | Real estate | 2020 |
| L F Marketing Consultants Ltd | Professional & scientific | 2015 |
| L J Nicol Electrical Ltd | Construction | 2012 |
| L M Property Services Limited | Construction | 2025 |
| L T Controls Ltd | Manufacturing | 2009 |
| L&T Realty Holdings Ltd | Real estate | 2021 |
| L.A Landscapes & Groundworks Ltd | Construction | 2025 |
| LA Mechanical Services Ltd | Construction | 2025 |
| Labrador Film Services (England) Limited | Information & communication | 2002 |
| Lacemakers Close Limited | Households | 2009 |
| Lacemakers Court Limited | Professional & scientific | 2005 |
| Lahori Student Biryani Limited | Wholesale & retail | 2023 |
| Lakeside Business Units Limited | Construction | 1999 |
| Lamf JN Ltd | Information & communication | 2016 |
| Lamf Ronaldinho Limited | Information & communication | 2019 |
| Lamf TC Ltd. | Information & communication | 2015 |
| Lamport Consulting Limited | Professional & scientific | 2020 |
| Land-Ban Limited | Construction | 2022 |
| Landlord Renovations Ltd | Administrative & support | 2015 |
| Landscaping & Agricultural Services Ltd | Administrative & support | 2010 |
| Lang Boon Ltd | Other services | 2022 |
| Lapithos Ltd | Administrative & support | 2017 |
| Laser Engraving Limited | Professional & scientific | 2002 |
| Lawnscience (Northants) Ltd | Administrative & support | 2007 |
| Lawnscience Epsom Limited | Administrative & support | 2021 |
| Lawnscience North Leeds Limited | Administrative & support | 2016 |
| Lawnscience North Worcestershire Ltd | Administrative & support | 2014 |
| Lawnscience Solihull Ltd | Administrative & support | 2011 |
| Lawrence & Sons Properties Ltd | Construction | 2026 |
| Lazery Attack Limited | Information & communication | 2018 |
| LB Management Ltd | Real estate | 2020 |
| LC Forklifts Limited | Construction | 2016 |
| LE Fevre Holdings Limited | Financial services | 2018 |
| Leach Farms Limited | Agriculture & fishing | 2006 |
| Lean Supply Chain Limited | Administrative & support | 2025 |
| Learn English Weekly Digital Learning Ltd | Information & communication | 2025 |
| Learn Guitar MK Ltd | Administrative & support | 2014 |
| Leeway Trading Limited | Administrative & support | 2008 |
| Lefebvre Associates Ltd | Administrative & support | 2012 |
| Lenborough Group Limited | Professional & scientific | 2019 |
| Leopold & Florence Limited | Arts & recreation | 2017 |
| Leopold and Lupo Limited | Information & communication | 2025 |
| LES Golding Ltd | Professional & scientific | 2013 |