| Joy Harvey Jones Limited | Administrative & support | 2012 |
| JP Roofing Services (Huthwaite) Limited | Construction | 2025 |
| JPC Construction (Midlands) Ltd | Construction | 2013 |
| JPC Door Sets Limited | Construction | 2019 |
| JPC Electrical Ltd | Construction | 2025 |
| JPC Joinery Ltd | Construction | 2020 |
| JPI Consultants Ltd | Professional & scientific | 2019 |
| JRA Foods Ltd | Hospitality | 2009 |
| JRF Homes Limited | Professional & scientific | 2020 |
| JS RL Ltd | Other services | 2018 |
| JSE Property Services Ltd | Real estate | 2024 |
| JSH Property Rentals Limited | Real estate | 2018 |
| JSR Healthcare Limited | Health & social care | 2018 |
| JT Consulting Solutions Ltd | Extraterritorial | 2024 |
| JT Joinery (Midlands) Ltd | Construction | 2014 |
| JT Web Limited | Information & communication | 2024 |
| JTJ Holdings Limited | Financial services | 2016 |
| JTS Contractors Ltd | Construction | 2026 |
| Judan Law Ltd | Professional & scientific | 2017 |
| Judd ENT Limited | Administrative & support | 2014 |
| Judd Group Limited | Financial services | 2018 |
| Jukes & Aston Funeral Services Ltd | Other services | 2022 |
| Jukes Group Limited | Professional & scientific | 2016 |
| Jukes Properties Limited | Real estate | 2002 |
| June Gaskin Aesthetics Ltd | Other services | 2024 |
| Jungle Puffin Holdings Limited | Financial services | 2024 |
| Just a Walk in the Park Limited | Other services | 2016 |
| Just Food Restaurant Limited | Hospitality | 2015 |
| Just Keep Talking Ltd. | Health & social care | 2014 |
| Just Tickety BOO Events Limited | Arts & recreation | 2015 |
| JV Landscapes Ltd | Administrative & support | 2026 |
| JV Robinson Ltd | Real estate | 2020 |
| JW Shiel Ltd | Wholesale & retail | 2025 |
| K & F Townshend Ltd | Information & communication | 2023 |
| K & J Brickwork Ltd | Construction | 2020 |
| K & Sons Recruitment Ltd | Administrative & support | 2020 |
| K D J Holdings (Midlands) Limited | Financial services | 2025 |
| K Stevens Burntwood Limited | Administrative & support | 2011 |
| K W Plant Training Ltd | Administrative & support | 2024 |
| K&D Planning Ltd | Information & communication | 2014 |
| K-Lous Hair & Beauty Ltd | Other services | 2026 |
| K.M Bathrooms & Kitchens Limited | Construction | 2012 |
| K.P. Environmental & Civils Limited | Administrative & support | 2024 |
| K9 Acres Ltd | Arts & recreation | 2019 |
| Kabb Property Limited | Real estate | 2025 |
| KAI Pharma Limited | Wholesale & retail | 2023 |
| Kaidon AI Ltd | Administrative & support | 2026 |
| Kailua Partnership LLP | | 2022 |
| Kain Miller Developments Ltd | Construction | 2023 |
| Kain Miller Ltd | Professional & scientific | 2023 |
| Kaivory Construction Ltd | Construction | 2021 |
| Kaizen Growth Limited | Administrative & support | 2020 |
| Kalfab Holdings Limited | Real estate | 2009 |
| Kandola Real Estates Limited | Real estate | 2019 |
| Kaper Town Ltd | Health & social care | 2024 |
| Karas-Uk Ltd | Wholesale & retail | 2024 |
| Karen Tracey & Associates Limited | Professional & scientific | 2014 |
| Karib Kitchen Limited | Hospitality | 2018 |
| Karkadann Limited | Professional & scientific | 2018 |
| Kartar & Seibo Ltd | Professional & scientific | 2021 |
| KAT CAN Cars Ltd | Wholesale & retail | 2025 |
| Katarina Fitness Ltd | Other services | 2025 |
| Kavke Property Services Ltd | Real estate | 2024 |
| Kaweb Limited | Information & communication | 1999 |
| Kayhurst Finance Limited | Administrative & support | 1976 |
| KAZ Murray PT Ltd | Education | 2026 |
| Kazoo PSG Holdings Limited | Financial services | 2014 |
| Kazoo PSG Limited | Manufacturing | 2003 |
| KB Active Ltd | Arts & recreation | 2024 |
| KB Hand Carwash Ltd | Other services | 2021 |
| KB Martial Arts Ltd | Arts & recreation | 2025 |
| KBP Medical Ltd | Health & social care | 2021 |
| KBS Tyre & Battery Limited | Wholesale & retail | 2018 |
| KC Energy Limited | Manufacturing | 1968 |
| KCO Inline Ice Skating Limited | Arts & recreation | 2008 |
| KDL Investments Limited | Real estate | 2008 |
| KEA Clinic Ltd | Other services | 2025 |
| Kearsley Close (Seaton Delaval) Management Company Limited | Households | 1997 |
| Keech Investment Limited | Financial services | 2026 |
| Keelys LLP | | 2008 |
| Keep Fit With Kelly Ltd | Arts & recreation | 2020 |
| Keith Clarke Consulting Limited | Extraterritorial | 2014 |
| Keith Newton Logistics Ltd | Professional & scientific | 2012 |
| Kelechi Okereke Limited | Professional & scientific | 2017 |
| Kelo Designs Limited | Construction | 2016 |
| Kelsplash Limited | Arts & recreation | 2016 |
| Kembla Limited | Construction | 2020 |
| Kenny's Properties Ltd | Real estate | 2018 |
| Keno Catering Ltd | Hospitality | 2017 |
| Kerr Connect Limited | Professional & scientific | 2020 |
| Kershaw (DWK) Holdings Limited | Financial services | 2018 |
| Kevan Brighting Limited | Information & communication | 2014 |
| Kevin Colebatch Builders & Contractors Ltd | Construction | 2008 |
| Kevlar Investigations Ltd | Administrative & support | 2025 |
| Kewb Developments Ltd | Construction | 2024 |
| Key Land (Stafford) Ltd | Real estate | 2018 |
| Key Land Capital Limited | Construction | 2017 |
| Key Parking UK Ltd | Transport & logistics | 2022 |
| Key Renovations Limited | Construction | 2024 |
| Key Spaces (KLC) Ltd | Real estate | 2016 |