| Keith Barrett Sculpture Ltd | Arts & recreation | 2022 |
| Kelley Morgan Models Ltd | Professional & scientific | 2004 |
| Kennoway Enterprises (KEL) Ltd | Other services | 2024 |
| Kerwood Shaw Properties Ltd | Real estate | 2025 |
| Kesho Collective C.I.C. | Financial services | 2024 |
| Kestrel Safety Limited | Wholesale & retail | 2000 |
| KEVLAR78 Ltd | Professional & scientific | 2025 |
| Key Skills Training Ltd | Education | 2016 |
| Khanderson Properties Ltd | Real estate | 2025 |
| Kilburn Estates Limited | Real estate | 2025 |
| KILBURN67 Ltd | Professional & scientific | 2022 |
| Kiltech Limited | Real estate | 1994 |
| Kimage GAS Limited | Construction | 2025 |
| Kimberley Avenue 1966 Limited | Extraterritorial | 2014 |
| Kinisis Solutions Limited | Manufacturing | 2025 |
| Kirkdale 2000 Limited | Professional & scientific | 2000 |
| Kitchen Quartz and Granite Worktops Ltd | Manufacturing | 2022 |
| Kitwave Group Limited | Wholesale & retail | 2015 |
| Kitwave Investments Limited | Wholesale & retail | 2015 |
| Kitwave Limited | Wholesale & retail | 1987 |
| Kitwave One Limited | Wholesale & retail | 2011 |
| KIW Property Investments Limited | Real estate | 2018 |
| Kiwi Building & Maintenance Ltd | Construction | 2023 |
| Kiwigo (UK) Ltd | Information & communication | 2016 |
| KK Paints Ltd | Construction | 2026 |
| KKD Technology Solutions Limited | Information & communication | 2017 |
| KLS North East Ltd | Administrative & support | 2023 |
| Knightman and Such Ltd | Professional & scientific | 2022 |
| Knoodles Ltd | Hospitality | 2015 |
| Knowles Access Limited | Construction | 2022 |
| Kompass Holdings Limited | Professional & scientific | 2004 |
| Konquest Technology Ltd | Information & communication | 2018 |
| Kore Stays Ltd | Real estate | 2026 |
| Kore Systems Technology Ltd | Information & communication | 2024 |
| KPI Ventures Limited | Professional & scientific | 2020 |
| Kpsl Ltd | Information & communication | 2024 |
| Kraken Brickwork Ltd | Construction | 2021 |
| Krispers Chicken Limited | Hospitality | 2019 |
| Kristen Leigh Auctions Limited | Wholesale & retail | 2014 |
| Krj-Rigging Limited | Construction | 2025 |
| Kryptic Communications Limited | Information & communication | 2025 |
| KS Paintworx Ltd | Wholesale & retail | 2019 |
| KS Property Maintenance NE Limited | Construction | 2026 |
| KSB11 Ltd | Professional & scientific | 2025 |
| KSD Homecare Capital NE Limited | Health & social care | 2025 |
| KSG (North East) Ltd | Arts & recreation | 2017 |
| Kssg Services Limited | Professional & scientific | 2020 |
| Kurt Trading Ltd | Transport & logistics | 2025 |
| KW HD Brow and Lash Bar Ltd | Other services | 2021 |
| Kwikfast Enterprises Ltd | Wholesale & retail | 2016 |
| Kyles Legal Practice Ltd | Professional & scientific | 2010 |
| Kylie Developments Commercial Ltd | Construction | 2024 |
| Kyoob Ltd. | Professional & scientific | 2011 |
| KZ & N Investments Ltd | Real estate | 2025 |
| KZT Consultancy Limited | Administrative & support | 2023 |
| L & J Barbers Ltd | Other services | 2022 |
| L M Consulting Ltd | Information & communication | 2014 |
| L M G Fenwick Limited | Financial services | 2018 |
| L Q Hospitality Ltd | Manufacturing | 2022 |
| L&C Food Service Ltd | Hospitality | 2021 |
| L&G Accountancy Services Limited | Professional & scientific | 2014 |
| L&J2 Barber Ltd | Other services | 2025 |
| L.J.Hasnip-Walker & D.Walker TFY Limited | Administrative & support | 2025 |
| L2 Business Consulting Limited | Professional & scientific | 2007 |
| L337HAX Consulting Ltd | Information & communication | 2025 |
| LA Holdings NE Ltd | Real estate | 2025 |
| LA Property Trading Ltd | Real estate | 2024 |
| Laered LAR Ltd | Health & social care | 2026 |
| Lafem Trading and Projects Ltd | Wholesale & retail | 2019 |
| Lakes Holiday Cottages Limited | Real estate | 2020 |
| Lakeshore Accountants Ltd | Professional & scientific | 2025 |
| Lakeshore Business Management Services Ltd | Professional & scientific | 2026 |
| Lapland by Clare Limited | Administrative & support | 2024 |
| Larkspur Homes and Gardens Ltd | Professional & scientific | 2026 |
| Larry's Fishcakes Limited | Manufacturing | 2017 |
| Lasp Group Ltd | Other services | 2023 |
| Lateral Vision Limited | Professional & scientific | 2006 |
| Latertest Limited | Administrative & support | 1998 |
| Latirali Services Limited | Wholesale & retail | 2024 |
| Laura Fulcher Services Ltd | Professional & scientific | 2021 |
| Laurajadeconsulting Ltd | Professional & scientific | 2026 |
| Layford Creative Ltd | Professional & scientific | 2023 |
| LB Joinery (NE) Ltd | Construction | 2026 |
| LBH Limited | Other services | 2000 |
| Lbishopholdings Ltd | Financial services | 2025 |
| LCZ Transport Limited | Transport & logistics | 2024 |
| LD Plumbing, Heating & Drainage Ltd | Construction | 2021 |
| LDM Maintenance Limited | Construction | 2026 |
| Leanne Jade Ltd | Administrative & support | 2021 |
| Learn 2 Drive School of Motoring Limited | Education | 2023 |
| LED & Heating Ltd | Manufacturing | 2026 |
| LEE Armstrong(Contracts) Ltd | Construction | 2023 |
| Legacy Numismatics Ltd | Wholesale & retail | 2019 |
| Legge Roofing Ltd | Construction | 2025 |
| Leisure Studio Limited | Professional & scientific | 2023 |
| Lekto Woodfuels Ltd | Wholesale & retail | 2016 |
| Leo's Barber Ltd | Other services | 2023 |
| Leonova's Ltd | Hospitality | 2026 |
| Let's Stay There Ltd | Hospitality | 2025 |
| Let's Talk PPC Ltd | Professional & scientific | 2022 |