| Kerrison Facilities & Installations Ltd | Construction | 2022 |
| Kerrisons Residential Lettings Limited | Real estate | 2023 |
| KES Services (NE) Ltd | Construction | 2017 |
| Kevan Turnbull Plumbing & Heating Ltd | Construction | 2023 |
| Kevin WS Ltd | Manufacturing | 2025 |
| Kevlar Services Ltd | Professional & scientific | 2019 |
| Key Wealth Financial Management Limited | Administrative & support | 2014 |
| KEY4LETS Ltd | Real estate | 2011 |
| Keys Please Ltd | Real estate | 2020 |
| Keyspot Security Ltd | Manufacturing | 2025 |
| Keystore Jarrow Limited | Wholesale & retail | 2022 |
| KGS Energy Ltd | Professional & scientific | 2022 |
| KGX Productions Ltd | Information & communication | 2016 |
| KH C&S Engineering Ltd | Professional & scientific | 2021 |
| Khan Courier Services Limited | Transport & logistics | 2019 |
| Khan Eatery Ltd | Hospitality | 2019 |
| KHN Building Contractors Ltd | Construction | 2024 |
| Khvz Ltd | Hospitality | 2017 |
| Kiasha Ltd | Other services | 2026 |
| Kiddycover Limited | Wholesale & retail | 2003 |
| Kids KLOSET24 Ltd | Wholesale & retail | 2024 |
| Kieran Gorman Boxing Ltd | Arts & recreation | 2026 |
| Kieron & Lauren Property Management Ltd | Real estate | 2024 |
| Killer Comps Ltd | Wholesale & retail | 2026 |
| Killer Strength Ltd | Other services | 2026 |
| Kiln Associates Limited | Health & social care | 2023 |
| Kilo Alfa Limited | Professional & scientific | 2014 |
| Kindling Therapies CIC | Education | 2020 |
| King Brothers Bricklaying Contractors Limited | Construction | 1997 |
| King INK Community Interest Company | Arts & recreation | 2023 |
| King's Properties (North East) Limited | Real estate | 2018 |
| Kingdom Pro Services Limited | Construction | 2025 |
| Kings and Queens Competition Club Ltd | Arts & recreation | 2025 |
| Kings Maintenance Services Ltd | Manufacturing | 2015 |
| Kings Road Clinic Limited | Real estate | 2011 |
| Kingsland Wealth Management Limited | Financial services | 2002 |
| Kingston Park Properties Limited | Construction | 2021 |
| Kipps Webb Electrical Limited | Construction | 2017 |
| Kirk Alderson Safety Consultant Ltd | Administrative & support | 2022 |
| Kirkley Hall Limited | Hospitality | 1994 |
| Kirpa 13 Ltd | Real estate | 2025 |
| Kirtley Property Group Ltd | Real estate | 2026 |
| Kish Trim Ltd | Manufacturing | 2021 |
| Kitchensecretuk Limited | Hospitality | 2025 |
| KJ Renewable & Property Services Limited | Professional & scientific | 2025 |
| KJL Automotive Ltd | Wholesale & retail | 2026 |
| Kjsams Ltd | Manufacturing | 2024 |
| KJV Electrical Limited | Construction | 2008 |
| KK Barbers Ltd | Other services | 2019 |
| KK Health & Wellbeing Ltd | Health & social care | 2023 |
| KKP (Holdings) Ltd | Extraterritorial | 2018 |
| Kkrishna.Co.Uk Ltd | Wholesale & retail | 2023 |
| Kkvarnas Ltd | Transport & logistics | 2022 |
| KKW (Holdings) Ltd | Extraterritorial | 2018 |
| KLF Renewables Ltd | Manufacturing | 2024 |
| Klue Sounds Limited | Manufacturing | 2023 |
| Klue Studios Limited | Information & communication | 2024 |
| KM Boxing Limited | Arts & recreation | 2023 |
| KMA Northeast Ltd | Manufacturing | 2016 |
| Kmck Properties Ltd | Real estate | 2024 |
| Knight Jenkins Limited | Financial services | 2026 |
| KNS Retail Ltd | Wholesale & retail | 2023 |
| Kobs (NE) Ltd | Construction | 2020 |
| Kodesh Couture Ltd | Information & communication | 2025 |
| Koffie Co Limited | Hospitality | 2025 |
| KOG Holdings Ltd | Financial services | 2026 |
| Koli (UK) Ltd | Hospitality | 2014 |
| Kona ADI Mukk PVT Limited | Hospitality | 2025 |
| Kongburgers Limited | Hospitality | 2022 |
| Koochini Food Ltd | Hospitality | 2025 |
| Koochini Pizza Ltd | Hospitality | 2019 |
| Kookaburra Veterinary Practice Ltd | Professional & scientific | 2025 |
| Kookie Karate Management Ltd | Education | 2024 |
| Koriva Group Ltd | Information & communication | 2024 |
| Korosh Construction Ltd | Construction | 2025 |
| Kose Healthcare Ltd | Administrative & support | 2017 |
| Kottdante Ltd | Real estate | 2026 |
| KP C&F Solutions Limited | Administrative & support | 2012 |
| KP High Voltage Jointing Ltd | Construction | 2025 |
| KP Prime Ltd | Wholesale & retail | 2026 |
| KP Rain Ltd | Construction | 2016 |
| KP Solutions Ltd | Wholesale & retail | 2022 |
| KP Wind Ltd | Professional & scientific | 2025 |
| Kpmd & Co Limited | Energy | 2015 |
| KPS Property Soloutions Ltd | Households | 2025 |
| KR Logistics Limited | Transport & logistics | 2023 |
| Kraftsoft Ltd | Information & communication | 2025 |
| KRC Jointech Ltd | Construction | 2025 |
| Krcl Properties Limited | Real estate | 2024 |
| Kreatbiz Ltd | Wholesale & retail | 2026 |
| Kreatitvezshop Ltd | Wholesale & retail | 2024 |
| Krishna (Sunderland) Limited | Wholesale & retail | 2025 |
| Krishnan Enterprises Ltd | Wholesale & retail | 2019 |
| KRS Multimedia Ltd | Information & communication | 2019 |
| Krulox Limited | Manufacturing | 2020 |
| KS Nexus Group Ltd | Wholesale & retail | 2026 |
| Ksdjsales Ltd | Wholesale & retail | 2026 |
| KSF Facilities Management Limited | Administrative & support | 2007 |
| KSM Property Rental Ltd | Real estate | 2025 |
| Kspglobalservices Limited | Information & communication | 2022 |