| Just Property Ltd | Hospitality | 2025 |
| Just Wealth Management Limited | Financial services | 2014 |
| Justadesign Ltd | Professional & scientific | 2023 |
| Justice Reports Limited | Administrative & support | 2023 |
| Jvev Limited | Wholesale & retail | 2020 |
| JW Heating & Plumbing Ltd | Construction | 2020 |
| Jwct Limited | Information & communication | 2019 |
| JWL Midlands Limited | Professional & scientific | 2024 |
| JWZ LLP | | 2013 |
| JWZ Private Equity LLP | | 2013 |
| JYM Life Limited | Arts & recreation | 2017 |
| Jyoti.M Limited | Health & social care | 2015 |
| JZH Property Limited | Real estate | 2020 |
| JZH Real Estate Limited | Real estate | 2025 |
| K & C Brown Ltd | Professional & scientific | 2024 |
| K & S Assets Ltd | Construction | 2018 |
| K Accounting Ltd | Professional & scientific | 2020 |
| K Charters Limited | Administrative & support | 2006 |
| K Contracts (Consultancy) Limited | Administrative & support | 1991 |
| K D Scaffold Limited | Construction | 2013 |
| K Factor Consulting Ltd | Professional & scientific | 2018 |
| K G Properties Limited | Real estate | 2002 |
| K H C Motor Co. Ltd | Wholesale & retail | 2021 |
| K Hayes Engineering Limited | Construction | 2014 |
| K Optical Ltd | Wholesale & retail | 2021 |
| K S R L Ltd | Real estate | 2021 |
| K Shanmugam Limited | Health & social care | 2008 |
| K Simpkin & Co Ltd | Real estate | 2024 |
| K Walsh Construction Services Ltd | Construction | 2021 |
| K&D Insurance Brokers Ltd | Financial services | 2011 |
| K&J Hair Miles Ltd | Other services | 2020 |
| K&M Elleman Limited | Professional & scientific | 2019 |
| K&R Growth Ltd | Real estate | 2023 |
| K-Wing Developments Ltd | Real estate | 2026 |
| K. & a. Associates (UK) Limited | Wholesale & retail | 2003 |
| K. Spencer Building & Maintenance Limited | Construction | 2008 |
| K.D.E.S.Installations Limited | Construction | 1998 |
| K.J.R.S Properties Limited | Real estate | 2022 |
| K.P.S Show & Floor Services Limited | Construction | 2012 |
| K.S. Kang Limited | Health & social care | 2003 |
| K22 Productions Limited | Arts & recreation | 2009 |
| K2S Investments Limited | Real estate | 2020 |
| K3 Innovations Ltd | Professional & scientific | 2013 |
| K5PROPERTY Ltd | Real estate | 2024 |
| K9 Security & Detection Ltd | Administrative & support | 2021 |
| Kaaaast Productions Limited | Arts & recreation | 2015 |
| Kaasuk Ltd | Wholesale & retail | 2025 |
| Kabir Food and Wine Ltd | Wholesale & retail | 2025 |
| Kadyan EYE Care Limited | Health & social care | 2013 |
| Kahlosaints Ltd | Wholesale & retail | 2026 |
| KAI Wealth Consultancy Limited | Financial services | 2015 |
| Kainth Innovations Ltd | Wholesale & retail | 2022 |
| Kainth Limited | Wholesale & retail | 2025 |
| Kaiya Medical Limited | Health & social care | 2025 |
| Kaizen Prime Ltd | Health & social care | 2023 |
| Kaizen Talent Solutions Limited | Administrative & support | 2015 |
| Kaleidoscope Optical Accessories Ltd | Wholesale & retail | 2017 |
| Kalin Creative Ltd | Professional & scientific | 2020 |
| Kalinko Limited | Wholesale & retail | 2016 |
| Kameron Gent TM Ltd | Construction | 2024 |
| Kameti Limited | Extraterritorial | 2020 |
| Kamhdrives Limited | Transport & logistics | 2025 |
| Kaminski Properties Ltd | Real estate | 2025 |
| Kan&Home Limited | Real estate | 2026 |
| Kanani Healthcare Limited | Health & social care | 2023 |
| Kanbra Quality Limited | Wholesale & retail | 2017 |
| Kandahari Limited | Transport & logistics | 2020 |
| Kandola Consulting Limited | Information & communication | 2017 |
| Kandy Camz Ltd | Arts & recreation | 2025 |
| Kane TM Ltd | Construction | 2021 |
| Kanzen Planet Limited | Construction | 2025 |
| KAP Property Ltd | Real estate | 2018 |
| Kaper Creative Limited | Professional & scientific | 2014 |
| Kaper Holdings Limited | Financial services | 2025 |
| Kaper Properties Limited | Real estate | 2024 |
| Kaptec Telecoms Services Limited | Information & communication | 2012 |
| Kara 2016 Limited | Arts & recreation | 2016 |
| Karachi POP & Co. Limited | Manufacturing | 2025 |
| Karakoram Clothing Company Ltd | Wholesale & retail | 2024 |
| Karamanos Limited | Hospitality | 2020 |
| Karography Limited | Professional & scientific | 2025 |
| Karr Investment Ltd | Real estate | 2024 |
| Kash Building Ltd | Construction | 2024 |
| Kashmir Consultancy Ltd | Professional & scientific | 2025 |
| Kask Properties Limited | Real estate | 2016 |
| Kasl Paragon Ltd | Professional & scientific | 2023 |
| Katal Properties Limited | Hospitality | 2019 |
| Kate Consulting Ltd | Professional & scientific | 2023 |
| Kate&Ami Homes Ltd | Real estate | 2024 |
| Kath's Cafe and Irish Store Maypole Ltd | Wholesale & retail | 2024 |
| Katherine Draisey Limited | Wholesale & retail | 1972 |
| Kathrey Homes Limited | Health & social care | 2021 |
| Kathryn Lewis Limited | Professional & scientific | 2012 |
| Kathy Millatt Limited | Arts & recreation | 2015 |
| Katy Victoria Beauty & Aesthetics Ltd | Health & social care | 2020 |
| Kaur Analytics Ltd | Administrative & support | 2025 |
| Kav's Bathrooms Ltd | Construction | 2022 |
| Kavaclan Health Ltd | Health & social care | 2026 |
| Kavannagh Construction 2 Ltd | Construction | 2016 |
| Kavannagh PARTNERSHIP2 Ltd | Professional & scientific | 2017 |