| Joerg Geiger Ltd | Wholesale & retail | 2024 |
| JOG Consulting Services Ltd | Information & communication | 2015 |
| John Lunn Building Services Limited | Construction | 2012 |
| John Norris Decorators Limited | Households | 2025 |
| Johnny C Ventures Limited | Transport & logistics | 2015 |
| Join the BID Ltd | Arts & recreation | 2025 |
| Jones and Valley Farm LLP | | 2023 |
| Jools Leisure Ltd | Arts & recreation | 2007 |
| Jotsonn Properties Limited | Real estate | 2021 |
| Journeygreen Ltd | Manufacturing | 2009 |
| JPC Advisory Limited | Other services | 2021 |
| Jpjk Ltd | Construction | 2026 |
| JRC Cleaning Services Ltd | Administrative & support | 2015 |
| JTM Chilton Ltd | Information & communication | 2025 |
| Just - in Automotive Limited | Administrative & support | 2017 |
| Just Bikes (Andover) Ltd | Wholesale & retail | 2012 |
| Just Practice Limited | Hospitality | 2019 |
| Juto Technologies Limited | Information & communication | 2026 |
| Juvo Consulting Limited | Professional & scientific | 2020 |
| JVW Consultancy Ltd | Professional & scientific | 2024 |
| JWE Psychiatry Ltd | Health & social care | 2025 |
| JWM Plant Limited | Construction | 2017 |
| JXL Consultancy Ltd | Professional & scientific | 2023 |
| K & S Property Investments Limited | Real estate | 2016 |
| K H Refrigeration and Air Conditioning Limited | Construction | 2013 |
| K S & SON Shipping Ltd | Other services | 2022 |
| K.L.S. Logistics Ltd | Transport & logistics | 2016 |
| KA Andover Ltd | Hospitality | 2019 |
| Kadatam Limited | Professional & scientific | 2020 |
| Kado Catering Ltd | Hospitality | 2024 |
| Kalanchoe Ltd | Wholesale & retail | 2020 |
| Kalia Transport Ltd | Other services | 2018 |
| KAM Property Solutions Ltd | Construction | 2018 |
| Kamil Watroba Ltd | Transport & logistics | 2019 |
| Kaos &Co. Ltd | Other services | 2026 |
| KAP Industries Ltd | Other services | 2021 |
| Karen Birks Training Ltd | Health & social care | 2025 |
| Karkokli Limited | Health & social care | 2024 |
| Kastel Property Solutions Ltd | Real estate | 2018 |
| Kastra Roofing Solutions Ltd | Construction | 2023 |
| KAT Green Ltd | Health & social care | 2020 |
| Kathy Hams Bookkeeping and Accountancy Services Limited | Professional & scientific | 2025 |
| Katt Designs Limited | Information & communication | 2004 |
| KB Care Consultancy Ltd | Public administration | 2026 |
| KBC Films Ltd | Information & communication | 2011 |
| KBL Innovations Ltd | Construction | 2024 |
| KBW Group Limited | Real estate | 2020 |
| Kebab House Racing Team Limited | Wholesale & retail | 2025 |
| Keith Edwards Metalwork Ltd | Manufacturing | 2012 |
| Kemble Building Services Limited | Professional & scientific | 2014 |
| KEN Bulpitt Limited | Administrative & support | 2001 |
| KEN White Distribution Limited | Transport & logistics | 1980 |
| KEN White Holdings Limited | Professional & scientific | 2010 |
| Kennedy Captures Ltd | Professional & scientific | 2024 |
| Kent Property Limited | Real estate | 2015 |
| Kenyegon Limited | Health & social care | 2016 |
| Kernel Browne Limited | Professional & scientific | 2020 |
| Keybolt (Farmers) Limited | Professional & scientific | 1973 |
| Kflkeska Ltd | Transport & logistics | 2022 |
| Kgem Ltd | Other services | 2017 |
| KGF Cars Ltd | Transport & logistics | 2020 |
| KH Kitchens Limited | Construction | 2019 |
| Kieron Beattie Landscaping Limited | Construction | 1987 |
| KILO9 Ltd | Administrative & support | 2025 |
| Kimpton Land Holdings Limited | Real estate | 2023 |
| Kingfisher Cleaning and Supplies Limited | Administrative & support | 2003 |
| Kingfisher Mcnair Limited | Professional & scientific | 2024 |
| Kingsdown Joinery Ltd | Manufacturing | 2011 |
| Kingsgate Medical Ltd | Health & social care | 2021 |
| Kingsmead Wealth Limited | Financial services | 2017 |
| Kingsmill Cottages and Barns (Management) Company Limited | Real estate | 1996 |
| Kingston Construction (Hampshire) Limited | Construction | 2002 |
| Kinsmade Consult Ltd | Professional & scientific | 2019 |
| Kirkar Group of Companies Ltd | Households | 2024 |
| Kiro Foods Ltd | Wholesale & retail | 2025 |
| KIT Pest Limited | Wholesale & retail | 2022 |
| KJ Auto Tech Ltd | Wholesale & retail | 2025 |
| KJM Holdings (Hampshire) Limited | Financial services | 2024 |
| KMR Ltd | Health & social care | 2022 |
| Knowl Hill Farm Ltd | Real estate | 2023 |
| Knowle Property Limited | Real estate | 2022 |
| Knurd Ltd | Extraterritorial | 2019 |
| Kodai Clothing Limited | Manufacturing | 2015 |
| Kokonut Lighting & Interiors Ltd | Manufacturing | 2008 |
| Kokoon Coffee Limited | Hospitality | 2025 |
| Kolastock Limited | Wholesale & retail | 2023 |
| Koleci Construction Ltd | Construction | 2026 |
| Kong Scaffolding (Southern) Ltd | Construction | 2020 |
| Konnectglobal Hub Group Ltd | Wholesale & retail | 2026 |
| Kontra Ltd | Wholesale & retail | 2021 |
| Kooner Brothers Transport Limited | Transport & logistics | 2025 |
| Kooner Constructions Ltd | Construction | 2024 |
| Kott Soft Furnishings Limited | Other services | 2025 |
| KR Salisbury Ltd | Wholesale & retail | 2022 |
| KR Southampton Ltd | Hospitality | 2025 |
| Kristof&Co Ltd | Real estate | 2014 |
| Krok Ltd | Construction | 2014 |
| Kryptogym Ltd | Wholesale & retail | 2024 |
| Kudukart Ltd | Wholesale & retail | 2026 |
| Kumars Mini Mart Private Ltd | Wholesale & retail | 2022 |