| KAT Courier Ltd | Transport & logistics | 2018 |
| Kata Construction Ltd | Construction | 2018 |
| Kate Moore Creative Ltd | Wholesale & retail | 2020 |
| Kate Properties Limited | Real estate | 2025 |
| Kater Lodge Property Limited | Real estate | 2020 |
| Katie Salmon Limited | Professional & scientific | 2019 |
| Kation Ltd | Transport & logistics | 2020 |
| Kaushik Logistics Ltd | Transport & logistics | 2026 |
| Kavhomes Property Limited | Construction | 2022 |
| Kavhomes Property Management Limited | Real estate | 2015 |
| Kavod Care Limited | Health & social care | 2024 |
| KAY 2 Limited | Health & social care | 2019 |
| KAY2 Properties Limited | Real estate | 2021 |
| Kaya 49 Ltd | Hospitality | 2025 |
| Kaya Lounge Northampton Ltd | Hospitality | 2025 |
| Kaya Renovations Ltd | Construction | 2020 |
| Kaye & Rafferty Limited | Health & social care | 2014 |
| Kayleb Advisory & Technology Ltd | Information & communication | 2026 |
| Kaylie Cullen Celebrant Services Ltd | Other services | 2023 |
| KAZ Construction (Northampton) Limited | Construction | 2016 |
| KAZ Construction Ltd | Construction | 2022 |
| Kazman Intercontinental Limited | Wholesale & retail | 2025 |
| Kazmi Energy Assessors Ltd | Manufacturing | 2026 |
| KB Interiors & Construction Ltd | Construction | 2026 |
| KB Reality Ltd | Extraterritorial | 2011 |
| KBB Centre Ltd | Wholesale & retail | 2018 |
| KBD Sales & Lettings Ltd | Real estate | 2017 |
| KBE Transport Ltd | Transport & logistics | 2017 |
| Kbreports Limited | Health & social care | 2025 |
| KBS Beautyz Limited | Other services | 2025 |
| KC Property Maintenance Ltd | Real estate | 2025 |
| KC Technical Services Limited | Professional & scientific | 2016 |
| Kcia Ltd | Real estate | 2026 |
| KCL Partners Ltd | Real estate | 2015 |
| KD Civil Engineering Ltd | Construction | 2023 |
| KD Development Solutions Ltd | Real estate | 2025 |
| KDD Global Holding Limited | Financial services | 2026 |
| KDM Accountants Ltd | Professional & scientific | 2016 |
| KDM Logistics Ltd | Transport & logistics | 2025 |
| Kdmrl Ltd | Wholesale & retail | 2017 |
| KDP Building Limited | Construction | 2019 |
| KDP Care Limited | Health & social care | 2014 |
| KDR Events Limited | Hospitality | 2018 |
| KDS Services Limited | Administrative & support | 2007 |
| Kean Nakamura Promotions Ltd | Arts & recreation | 2020 |
| Keble Court (Wellingborough) Management Company Limited | Households | 2005 |
| Keefe Queue Limited | Information & communication | 2025 |
| Keegan Family Investments Ltd | Real estate | 2026 |
| Keep Cargo Ltd | Transport & logistics | 2021 |
| Keep Pushing Records Limited | Information & communication | 2024 |
| Kegworth 10 Renewables Ltd | Professional & scientific | 2023 |
| Kehkashan Management Consulting Ltd | Financial services | 2018 |
| Keir Wenham-Flatt Ltd | Arts & recreation | 2016 |
| Keith Garages Property Services Ltd | Real estate | 1953 |
| Keith's Helping Hands Ltd | Construction | 2025 |
| Kejja Motorsport Ltd | Wholesale & retail | 2015 |
| Kelch UK Limited | Manufacturing | 2004 |
| Kelevra Transport Ltd | Transport & logistics | 2025 |
| Kellex Electrical & Fire Protection Ltd | Professional & scientific | 2024 |
| Kelly Domiciliary Care Ltd | Health & social care | 2023 |
| Kellys Decorating Limited | Construction | 2018 |
| Kelmarsh (Events) Limited | Real estate | 2004 |
| Kelplin Solutions Ltd | Professional & scientific | 2026 |
| Kelsall IT Consultants Limited | Information & communication | 2020 |
| Kelta Limited | Financial services | 2014 |
| Keltone Limited | Wholesale & retail | 1986 |
| Kemdra Limited | Manufacturing | 2026 |
| Kemek Enterprise Ltd | Wholesale & retail | 2025 |
| Kemp Oak Limited | Administrative & support | 2022 |
| Kempton Retail Ltd | Wholesale & retail | 2026 |
| Kems GE Ltd | Wholesale & retail | 2025 |
| Kemshead Ltd | Agriculture & fishing | 2025 |
| Kenahost International Ltd | Wholesale & retail | 2020 |
| Kene Building Services Ltd | Construction | 2021 |
| Kennacott Management Limited | Hospitality | 2017 |
| Kennedy Logistics Ltd | Transport & logistics | 2021 |
| Kennedy Mortgage Practice Limited | Financial services | 2014 |
| Kennel Lane Management Company Limited | Households | 2010 |
| Kennington Arts Club Limited | Hospitality | 2021 |
| Kensington Scott Interiors Limited | Manufacturing | 2018 |
| Kent Electrical Company (Earls Barton) Ltd | Construction | 2015 |
| Kentech Business Solutions Ltd | Information & communication | 2021 |
| Kentkrew Ltd | Administrative & support | 2012 |
| Kents Hill (MK) Management Company Limited | Households | 1992 |
| Kenyer Ltd | Other services | 2018 |
| Kepler Engineering Ltd | Information & communication | 2025 |
| Keptar Films Ltd | Information & communication | 2023 |
| KER Mansion Residents Ltd | Administrative & support | 2017 |
| Kerala HUT Ltd | Hospitality | 2021 |
| Kerala Palace Limited | Hospitality | 2023 |
| Kerala Spices Ltd | Hospitality | 2023 |
| Keralicure Limited | Wholesale & retail | 2025 |
| Keraykevira Limited | Construction | 2023 |
| Kerb Race Solution Limited | Construction | 2023 |
| Kerbcraft Contractors Ltd | Construction | 2023 |
| Kerbstones & Asphalt Parking Limited | Construction | 2020 |
| Kern Controls Limited | Construction | 2026 |
| Kernel Live Ltd | Arts & recreation | 2017 |
| Kerpop Ltd | Wholesale & retail | 2024 |
| Kesa Estates Limited | Hospitality | 2022 |