| Kitty Properties Ltd | Extraterritorial | 2015 |
| Kivi Digital Limited | Information & communication | 2024 |
| KJM Plastering and Property Maintenance Contractors Limited | Construction | 2026 |
| KJR Lets Ltd | Real estate | 2020 |
| KK Accountancy Practice Ltd | Professional & scientific | 2015 |
| KKD Soft Play Ltd | Arts & recreation | 2013 |
| KL Agentic Limited | Information & communication | 2026 |
| KL Smith (NE) Roofing Contractors Ltd | Construction | 2024 |
| Klaus Care Ltd | Health & social care | 2017 |
| Klevva Ltd | Real estate | 2026 |
| KLG SRH Services Ltd | Health & social care | 2024 |
| KLS Builders Limited | Construction | 2019 |
| KLS Supplies Ltd | Wholesale & retail | 2003 |
| KM Innovative X Ltd | Information & communication | 2026 |
| KM Properties (NE) Ltd | Real estate | 2024 |
| KM Waste and Recycling Ltd | Water & waste | 2025 |
| Kmej Limited | Financial services | 2025 |
| KMH.29 Limited | Real estate | 2018 |
| Kmhaa Holdings Ltd | Real estate | 2021 |
| KMS Gateshead Ltd | Hospitality | 2024 |
| Knersh Ltd | Real estate | 2014 |
| Knet Services Ltd | Information & communication | 2025 |
| Knight Financial Ltd | Professional & scientific | 2021 |
| Know Your Floors CIC | Public administration | 2020 |
| Kokona Mortgage Solutions Ltd | Financial services | 2025 |
| KOL Bonayich Limited | Administrative & support | 2013 |
| Kolamba Fest Ltd | Hospitality | 2025 |
| Kolamba Town Ltd | Hospitality | 2025 |
| Kollel Shaarei Halacha | Education | 2010 |
| Konnectai Ltd | Information & communication | 2025 |
| Konsulting Limited | Information & communication | 2004 |
| Koppu Ltd | Manufacturing | 2025 |
| Kopycat Promotions Limited | Arts & recreation | 2022 |
| Kopycats Ltd | Arts & recreation | 2020 |
| Koroneos Ltd | Health & social care | 2014 |
| Koshy Associates Limited | Administrative & support | 2019 |
| Kotiaooh Ltd | Wholesale & retail | 2026 |
| Kovic Services Limited | Professional & scientific | 2024 |
| Kovr Ltd | Manufacturing | 2026 |
| Kozyful Ltd | Wholesale & retail | 2024 |
| KP Manufacturing Ltd | Manufacturing | 2026 |
| KPM Fylde Partnership Limited | Health & social care | 2014 |
| Kproperty Ltd | Real estate | 2012 |
| KR Tasker Digital Ltd | Professional & scientific | 2024 |
| Kraiganne Properties Ltd | Real estate | 2018 |
| Kramnai Ltd | Real estate | 2022 |
| Kratos Communications Limited | Manufacturing | 2009 |
| Kratos Holdings U K Limited | Professional & scientific | 2016 |
| Krcm Transport Limited | Transport & logistics | 2026 |
| KRS Recovery NE Ltd | Wholesale & retail | 2022 |
| Krypton IT (North East) Limited | Information & communication | 2013 |
| KS Aesthetics & Beauty Ltd | Other services | 2023 |
| KS Safety Consultancy Ltd | Professional & scientific | 2025 |
| KSB Traders Limited | Wholesale & retail | 2025 |
| Ksha Investments Ltd | Real estate | 2023 |
| KSK Services (NE) Ltd. | Real estate | 2015 |
| KSL Ventures Ltd | Real estate | 2018 |
| KSR Real Estate Ltd | Real estate | 2025 |
| KSS Selenity Ltd | Health & social care | 2023 |
| Kt-Tek Ltd | Wholesale & retail | 2022 |
| KTD (NE) Limited | Wholesale & retail | 2012 |
| Ktrust Ltd | Health & social care | 2021 |
| Kuhamia Healthcare Staffing Ltd | Administrative & support | 2021 |
| Kult North East Ltd | Wholesale & retail | 2025 |
| Kundan Medical Services Ltd | Health & social care | 2017 |
| Kunle Adewale Company Limited | Wholesale & retail | 2025 |
| Kuro Dragon Limited | Information & communication | 2010 |
| Kurum Group Limited | Real estate | 2023 |
| Kutchenkommode Ltd | Wholesale & retail | 2025 |
| KV Electrical Engineering Limited | Administrative & support | 2015 |
| KWR Sports Ltd | Arts & recreation | 2020 |
| L & a Inspection Services Limited | Professional & scientific | 2024 |
| L & D Education Ltd | Education | 2019 |
| L E F Engineering Limited | Information & communication | 2017 |
| L G Johnson Property Ltd | Real estate | 2024 |
| L L Car Valeting Ltd | Wholesale & retail | 2025 |
| L N Food Ltd | Hospitality | 2025 |
| L O K Property Ltd | Real estate | 2025 |
| L Stewart Roofing Limited | Construction | 2026 |
| L. D. a. Consultants Limited | Professional & scientific | 2012 |
| L.A.Medical Services Limited | Health & social care | 2017 |
| L8R@WARDLEY C.I.C. | Health & social care | 2019 |
| LA Derma Aesthetic Ltd | Other services | 2025 |
| LA Pergola & Co Ltd | Hospitality | 2025 |
| LAB Group Services Limited | Information & communication | 2019 |
| Label LAB (NE) Ltd | Manufacturing | 2023 |
| Lady Dee’S Kitchen Ltd | Hospitality | 2025 |
| Ladybird's Childrens Nursery Limited | Health & social care | 2004 |
| LAG Insulation Ltd | Construction | 2025 |
| LAG Media Ltd | Professional & scientific | 2026 |
| Laisidris Medical Services Ltd | Health & social care | 2025 |
| Lakeland Outdoor Fixings Limited | Manufacturing | 2015 |
| Lakeside DC Ltd | Hospitality | 2026 |
| Lakshmihari Consultancy Ltd | Health & social care | 2026 |
| LAL Real Estate Ltd | Real estate | 2026 |
| Lally Real Estate Ltd | Real estate | 2018 |
| Lambert Taylor & Gregory Solicitors LLP | | 2025 |
| Lamesley Childcare | Administrative & support | 2007 |
| LAN Project Ltd | Real estate | 2024 |
| Lana Trading Limited | Wholesale & retail | 2023 |