| Kandiah Limited | Wholesale & retail | 2015 |
| Kandlelyght Services Limited | Administrative & support | 2024 |
| Kantira Limited | Real estate | 2021 |
| Kapoor Estates Ltd | Professional & scientific | 1996 |
| Karageorgiou Ltd | Health & social care | 2022 |
| Karaka Limited | Professional & scientific | 2003 |
| Karakurt Bookkeeping Limited | Professional & scientific | 2022 |
| KAS Business Solutions Ltd | Professional & scientific | 2008 |
| Kashyap & Son's Investments Ltd | Real estate | 2025 |
| Katamy Limited | Real estate | 2012 |
| Katell Property Maintenance Limited | Administrative & support | 2004 |
| Katoa Kitchens Ltd | Construction | 2008 |
| Kavach Ltd | Financial services | 2026 |
| Kavit Shah Ltd | Professional & scientific | 2023 |
| Kazik CH Building Limited | Construction | 2022 |
| Kazura Ltd | Wholesale & retail | 2019 |
| KB Clinical Research Limited | Professional & scientific | 2010 |
| KCJ Scenic Painting Limited | Information & communication | 2025 |
| KE Accountancy Limited | Professional & scientific | 2022 |
| Keel Developments Limited | Construction | 2016 |
| Keel Homes Limited | Real estate | 2004 |
| Kellett Recruitment Limited | Administrative & support | 2020 |
| KEM Associates Limited | Administrative & support | 2002 |
| Kemistry of Style by G6 Limited | Professional & scientific | 2022 |
| Kennedy Bros Ltd | Real estate | 2024 |
| Kenton Developers Ltd | Construction | 2017 |
| Kerryford Limited | Professional & scientific | 2012 |
| Kerryford M&E Limited | Professional & scientific | 2023 |
| KES85 Limited | Real estate | 2021 |
| Keston College | Arts & recreation | 1970 |
| Kettlefish Productions Ltd | Professional & scientific | 2010 |
| Keval Psychotherapy Ltd | Health & social care | 2014 |
| Kevin Callanan Camera Limited | Professional & scientific | 2015 |
| Keyway Estates Limited | Construction | 2000 |
| KFX Holdings Ltd | Hospitality | 2019 |
| KG Local Ltd | Wholesale & retail | 2024 |
| KH GAS Ltd | Construction | 2021 |
| Kiddies Island Hair Salon Ltd | Other services | 2025 |
| Kidner Orthodontics Limited | Health & social care | 2018 |
| Kidney Care for ALL | Education | 2022 |
| KIG Professional Nannies Ltd | Administrative & support | 2022 |
| Kikatex Ltd | Wholesale & retail | 1991 |
| Kildare Management Limited | Households | 2006 |
| Kilfera Limited | Construction | 2007 |
| Killpattern Limited | Professional & scientific | 2020 |
| Killybegs Investments Limited | Financial services | 2023 |
| Kilomi Limited | Real estate | 2021 |
| KIM & GM Investments Ltd | Households | 2023 |
| KIM Daniels Communications Ltd | Professional & scientific | 2019 |
| Kimball Consulting Limited | Professional & scientific | 1998 |
| Kimball Properties Ltd | Real estate | 2017 |
| Kimberly Wyatt Dance Academy Ltd | Administrative & support | 2014 |
| Kimi Foods Ltd | Hospitality | 2023 |
| Kindrelle Limited | Information & communication | 2025 |
| Kinetech Limited | Information & communication | 2010 |
| Kingdom Carpentry Limited | Construction | 2010 |
| Kingfisher School of Swimming LLP | | 2025 |
| Kingman Consulting Limited | Professional & scientific | 2025 |
| Kingterior Ltd | Professional & scientific | 2021 |
| Kiota UK One Ltd | Real estate | 2017 |
| KIP Media Ltd | Professional & scientific | 2013 |
| Kirans Hairstyles Limited | Other services | 2020 |
| Kirstie LE Marque Limited | Manufacturing | 2020 |
| Kitashu Ltd | Real estate | 2016 |
| KJ Stunts Limited | Information & communication | 2015 |
| KJB Medical Ltd | Health & social care | 2018 |
| KJE Pubs Ltd | Hospitality | 2017 |
| Kjeldsen Aitken Ltd | Professional & scientific | 2025 |
| KKC 1 Ltd | Real estate | 2024 |
| KKC Accountants Limited | Professional & scientific | 2013 |
| Klassydrinkzz Ltd | Wholesale & retail | 2026 |
| Kleanwell Limited | Administrative & support | 1999 |
| Klime 8 Impact Ltd | Professional & scientific | 2023 |
| KLP Care Ltd | Health & social care | 2019 |
| KM10 Estates Limited | Real estate | 2025 |
| Kmco Converged IP Services Limited | Professional & scientific | 2008 |
| Kmco Group Limited | Information & communication | 2008 |
| Kmco Group Telecoms Ltd | Information & communication | 2026 |
| Kmco TM Solutions Limited | Construction | 2014 |
| KMH Consulting Ltd | Professional & scientific | 2023 |
| KNE Holdings Limited | Financial services | 2020 |
| Knight IT Consultancy Ltd | Information & communication | 2019 |
| Knights Green Ltd | Households | 2011 |
| Knit Craft International Ltd | Wholesale & retail | 2015 |
| KNJ Murphy Ltd | Extraterritorial | 2025 |
| Knock OFF Music Limited | Information & communication | 2018 |
| Knockdomney Obair Limited | Information & communication | 1998 |
| Knot Pure Limited | Extraterritorial | 2022 |
| KNX UK Limited | Professional & scientific | 2006 |
| Komveo IT Solutions Ltd | Information & communication | 2015 |
| Konnect Kapital Finance Limited | Financial services | 2021 |
| Kore Konceptz Ltd | Professional & scientific | 2021 |
| Koshal & Co Limited | Real estate | 2013 |
| KP House Management Co Limited | Real estate | 2015 |
| KPU Solutions Ltd | Manufacturing | 2022 |
| KR Product Consulting Ltd | Information & communication | 2026 |
| KR Vinayaga Property Investments Ltd | Real estate | 2024 |
| KRB Leisure Limited | Wholesale & retail | 2021 |
| Krestfield Consultancy Limited | Professional & scientific | 2008 |
| Krista Ltd | Transport & logistics | 2020 |