| KM Therapy Limited | Health & social care | 2012 |
| KMH Capital Ltd | Professional & scientific | 2017 |
| KMH Investments Limited | Real estate | 2020 |
| Knight PM Consultancy Ltd | Construction | 2017 |
| Knock Knock Financial Limited | Financial services | 2006 |
| Knock Knock Residential Ltd | Real estate | 2015 |
| Knockout Fitness Limited | Other services | 2017 |
| Koig Limited | Information & communication | 2025 |
| Kolor Pro UK Ltd | Extraterritorial | 2024 |
| KOM Associates Limited | Professional & scientific | 2025 |
| Koppers Performance Chemicals UK Limited | Manufacturing | 1995 |
| Kora Music Education Ltd | Education | 2025 |
| Kos's Barbers Ltd | Other services | 2019 |
| Koshy Foods Ltd | Hospitality | 2024 |
| Kotis Electricians Limited | Construction | 2013 |
| Kovy Services Ltd | Other services | 2019 |
| KP Direct Ltd | Professional & scientific | 2026 |
| KPS Civil Site Engineering Ltd | Construction | 2023 |
| Kreative Security Group Limited | Financial services | 2019 |
| Kreative Tech Ltd | Information & communication | 2018 |
| Kreston Clive Owen LLP | | 2011 |
| KRH Watches Limited | Wholesale & retail | 2024 |
| Kroop Group Ltd | Transport & logistics | 2020 |
| Krul Ltd | Wholesale & retail | 2017 |
| Krystabells Limited | Other services | 2024 |
| KS Literacy Boosters Limited | Education | 2026 |
| Ksahin Limited | Administrative & support | 2017 |
| KSJ Homes Ltd | Real estate | 2025 |
| KSM SAM Limited | Hospitality | 2022 |
| KSW Consultancy Limited | Professional & scientific | 2008 |
| Kudos Cards Ltd | Manufacturing | 2025 |
| Kush Drinks Ltd | Manufacturing | 2021 |
| Kvar Engineering Services Limited | Construction | 2007 |
| KVL Installations Limited | Construction | 2019 |
| KWR Limited | Manufacturing | 2025 |
| KY Trading Limited | Wholesale & retail | 2023 |
| Kyle Blundell Ltd | Construction | 2026 |
| Kyle Lawson Ltd | Administrative & support | 2026 |
| Kytun (UK) Ltd | Manufacturing | 2010 |
| L & G Work Surfaces Limited | Manufacturing | 2020 |
| L & L Estates NE Ltd | Real estate | 2025 |
| L a Tomlinson Psychology Services Limited | Health & social care | 2024 |
| L a Roofers Ltd | Construction | 2014 |
| L Embleton Property Limited | Real estate | 2023 |
| L Graney Plumbing & Heating Ltd | Construction | 2021 |
| L J Barbers Ltd | Other services | 2015 |
| L J H Forestry Ltd | Agriculture & fishing | 2024 |
| L M W Trading Ltd | Wholesale & retail | 2017 |
| L W Home Improvements Ltd | Construction | 2023 |
| L W Home Services Ltd | Construction | 2025 |
| L&C Construction Limited | Construction | 2021 |
| L&M Race Paving Limited | Construction | 2017 |
| L&N Travel Ltd | Administrative & support | 2024 |
| L&S Equine Transport Ltd | Transport & logistics | 2023 |
| L.A Facilities Management Ltd | Administrative & support | 2025 |
| L2AP Property Ltd | Real estate | 2023 |
| L4 Projects Ltd | Construction | 2019 |
| LA Joinery NE Ltd | Construction | 2025 |
| LA Jolie Dent Ltd | Health & social care | 2024 |
| LA Linguistica Ltd | Professional & scientific | 2015 |
| LA Pizza and Catering Ltd | Hospitality | 2025 |
| LA Pizza NE Ltd | Hospitality | 2022 |
| LA Vino (BA) Ltd | Hospitality | 2021 |
| LA Vita Hurworth Ltd | Hospitality | 2025 |
| LAB HAN Ltd | Health & social care | 2022 |
| LAB Tech North East Limited | Other services | 2015 |
| Labosia Ltd | Wholesale & retail | 2026 |
| Laing Psychology Limited | Education | 2023 |
| Laing's Detailing Valeting Ltd | Wholesale & retail | 2026 |
| Lakrown Couture Ltd | Manufacturing | 2026 |
| Laluna Group IT Ltd | Financial services | 2023 |
| Lamb Bookkeeping and Accounts Ltd | Professional & scientific | 2024 |
| Lambert Trades Ltd | Construction | 2025 |
| Laminar Automation Limited | Information & communication | 2013 |
| Land and Marine Ltd | Administrative & support | 2020 |
| Landlords 2 Ltd | Real estate | 2008 |
| LANE7 a Ltd | Arts & recreation | 2022 |
| LANE7 AA Ltd | Arts & recreation | 2025 |
| LANE7 Aberdeen Ltd | Arts & recreation | 2016 |
| LANE7 Arthur Ltd | Arts & recreation | 2020 |
| LANE7 B Ltd | Arts & recreation | 2022 |
| LANE7 Birmingham Ltd | Arts & recreation | 2016 |
| LANE7 Bristol Ltd | Arts & recreation | 2016 |
| LANE7 C Ltd | Arts & recreation | 2022 |
| LANE7 D Ltd | Arts & recreation | 2022 |
| LANE7 Durham Ltd | Arts & recreation | 2017 |
| LANE7 E Ltd | Arts & recreation | 2022 |
| LANE7 F Ltd | Arts & recreation | 2022 |
| LANE7 G Ltd | Arts & recreation | 2022 |
| LANE7 H Ltd | Arts & recreation | 2022 |
| LANE7 Holdings Limited | Financial services | 2025 |
| LANE7 HR Ltd | Professional & scientific | 2019 |
| LANE7 I Ltd | Arts & recreation | 2022 |
| LANE7 J Ltd | Arts & recreation | 2022 |
| LANE7 K Ltd | Arts & recreation | 2024 |
| LANE7 L Ltd | Arts & recreation | 2024 |
| LANE7 Leicester Ltd | Arts & recreation | 2016 |
| LANE7 Liverpool Ltd | Arts & recreation | 2017 |
| LANE7 Ltd | Financial services | 2013 |
| LANE7 M Ltd | Arts & recreation | 2024 |