| JR Revell Fire & Security Ltd | Construction | 2025 |
| JR Revell Group Limited | Financial services | 2026 |
| JR Revell Ltd | Construction | 2016 |
| JR Revell M&E Ltd | Construction | 2020 |
| JR Revell Renewables Ltd | Construction | 2025 |
| JR Revell Temporary Services Ltd | Construction | 2025 |
| JRC Accounts & Tax LLP | | 2017 |
| JRC Digital Limited | Administrative & support | 2021 |
| JRS Tech Ltd | Wholesale & retail | 2014 |
| JSC Developments Ltd | Real estate | 2025 |
| Jukups Limited | Professional & scientific | 2010 |
| Julia Osborne Consulting Ltd | Professional & scientific | 2009 |
| JW Childcare Holding Limited | Financial services | 2024 |
| JW Pilates Petersfield Limited | Arts & recreation | 2025 |
| JW Pilates Woking Limited | Arts & recreation | 2026 |
| JW W & B Adams Holdings Limited | Financial services | 2022 |
| JW W & B Adams Partnership Limited | Real estate | 2017 |
| JWB Carpentry & Building Ltd | Construction | 2020 |
| Jwcse Ltd | Professional & scientific | 2020 |
| JXE Carpentry & Construction Ltd | Construction | 2022 |
| K & B Events Ltd | Arts & recreation | 2020 |
| K & M Roofing Construction Limited | Construction | 2002 |
| K W 2 Limited | Manufacturing | 2011 |
| K. Barbers Emporium (Billericay) Limited | Other services | 2017 |
| K. Barbers Emporium Limited | Other services | 2007 |
| K.G.Plastering Limited | Construction | 2019 |
| K.P.M. Rock Limited | Real estate | 2001 |
| Kaduct Ltd | Wholesale & retail | 2026 |
| Kaiona Beach Wear Ltd | Wholesale & retail | 2025 |
| Kalistar LLP | | 2005 |
| KAM Hardware Ltd | Wholesale & retail | 2001 |
| Karen Collier Careers Limited | Professional & scientific | 2010 |
| Karino Holdings Limited | Real estate | 2025 |
| Katie Cole Limited | Manufacturing | 2026 |
| Katie Robinson Human Factors Limited | Professional & scientific | 2005 |
| KBL Communications Limited | Construction | 2019 |
| Kean Street Management Company Limited | Construction | 2000 |
| Keerthi Pratyusha Properties Ltd | Real estate | 2026 |
| Kellow Health Ltd | Other services | 2009 |
| Kelly Parrish Recruitment Limited | Professional & scientific | 2023 |
| Kelvedon Village Developments Ltd | Construction | 2021 |
| Kelvik Construction Limited | Construction | 2000 |
| Kensington Court Flats Limited | Households | 2001 |
| Kesbond Limited | Manufacturing | 1986 |
| Kesely Landscapes Limited | Professional & scientific | 2017 |
| Kestrel Environmental Services Limited | Administrative & support | 2004 |
| Key Largo Shutters Ltd | Wholesale & retail | 2018 |
| Keystones Maintenance Ltd | Other services | 2025 |
| Keystones Property Ltd | Real estate | 2013 |
| KEZ Catering Ltd | Hospitality | 2025 |
| KG Window Supplies Limited | Wholesale & retail | 2023 |
| KH Land Holdings Limited | Construction | 2005 |
| Khookie Limited | Hospitality | 2024 |
| Kiambu Properties Ltd | Real estate | 2025 |
| Kickz N MIX Emporium Ltd | Wholesale & retail | 2026 |
| Killick Martin Chartering Limited | Transport & logistics | 2018 |
| Killick Martin Group Limited | Transport & logistics | 2017 |
| Killick Martin International Limited | Transport & logistics | 2018 |
| Kimbolton Electronics Limited | Manufacturing | 1995 |
| Kinfauns Road (Block B) Management Company Limited | Real estate | 1992 |
| Kinfauns Road (Block F) Management Company Limited | Professional & scientific | 1992 |
| Kinfauns Road (Block G) Management Company Limited | Real estate | 1992 |
| Kinfauns Road (Block H) Management Company Limited | Real estate | 1992 |
| Kinfauns Road (Block P) Management Company Limited | Real estate | 1992 |
| Kingsley (Grays) Limited | Other services | 1970 |
| Kinsbourne Common Nursery & Pre-School Limited | Education | 2026 |
| Kitts (Billericay) Limited | Extraterritorial | 2001 |
| KJ Statistical Consulting Ltd | Professional & scientific | 2026 |
| KJ Sustainability Consultancy Ltd | Other services | 2020 |
| KJB Cleaning Limited | Administrative & support | 2015 |
| Kjjjtm Ltd | Administrative & support | 2021 |
| KJR Contracts Limited | Agriculture & fishing | 2014 |
| KKD Solutions Limited | Professional & scientific | 2024 |
| KLM Productions Ltd | Professional & scientific | 2022 |
| Koached by Kieran Ltd | Education | 2025 |
| Kosk Restaurant PVT Ltd. | Hospitality | 2016 |
| Kozanecki Food Company Ltd | Wholesale & retail | 2017 |
| KPB Properties Ltd | Real estate | 2022 |
| KR Whiteley Building Contractors Limited | Construction | 2018 |
| KSP Liner Limited | Extraterritorial | 2011 |
| KSQ2 Ltd | Construction | 2022 |
| KT Equine Limited | Information & communication | 2021 |
| Kuick Fire Sprinklers Limited | Construction | 2008 |
| L & L Commercial Properties Ltd | Real estate | 2020 |
| L a S Partnership Limited | Professional & scientific | 2012 |
| L and S Essex Limited | Real estate | 2024 |
| L E Carr & Sons Sporting Ltd | Agriculture & fishing | 2019 |
| L Foster Site Surveying Ltd | Construction | 2021 |
| L S Investment Management Limited | Administrative & support | 2009 |
| L T H Farms Ltd | Agriculture & fishing | 2008 |
| L.E.A. Investment Management Limited | Real estate | 2003 |
| L.E.A. Investments (Haverhill) Limited | Real estate | 2000 |
| L.T Flooring Ltd | Construction | 2007 |
| LA Base Pizza Ltd | Hospitality | 2022 |
| LA Salette Catholic Club Limited | Other services | 2002 |
| LA Sky Limited | Information & communication | 2021 |
| Lagal Investments Ltd | Real estate | 2024 |
| Lambton & Jackson Ltd | Hospitality | 2014 |
| Lancet Property Ltd | Real estate | 2010 |
| Landbreach Limited | Construction | 1982 |