| JW Building Services North East Ltd | Construction | 2019 |
| JW Industrial Services Ltd | Construction | 2024 |
| JW Properties & Services Ltd | Construction | 2026 |
| K & S Motor Engineers Limited | Wholesale & retail | 2017 |
| Kafiga Landings Association Ltd | Arts & recreation | 2020 |
| Kanavy's Holding Limited | Real estate | 2024 |
| Kanavy's Limited | Wholesale & retail | 2017 |
| Karen’S Coaching Ltd | Health & social care | 2025 |
| Kate Baxter Properties Ltd | Real estate | 2024 |
| Katnipp Studios Limited | Arts & recreation | 2019 |
| Kayls Clothing Ltd | Wholesale & retail | 2026 |
| Keith Addison Logistics Ltd | Transport & logistics | 2024 |
| Keith Harrington 66 Ltd | Construction | 2026 |
| Kelso Micropub Ltd | Hospitality | 2020 |
| Kentucky Transport Limited | Transport & logistics | 2026 |
| Kerrs' Carpet & BED Warehouse Ltd | Wholesale & retail | 2012 |
| Kevin D Westwood Associates Ltd | Wholesale & retail | 2021 |
| Keywise National Ltd | Real estate | 2013 |
| KG Properties Teesside Limited | Real estate | 2026 |
| Kitted Football Limited | Information & communication | 2024 |
| KJ Hospitality Ltd | Hospitality | 2024 |
| KK Access Solutions Ltd | Construction | 2025 |
| KKR23 Ltd | Other services | 2023 |
| Klmulh Limited | Wholesale & retail | 2026 |
| KM Hire Ltd | Construction | 2023 |
| KMC Management Services Limited | Construction | 2024 |
| KMD Electrical Ltd | Construction | 2026 |
| Kngzcompany Ltd | Wholesale & retail | 2024 |
| Knights Catering Services Ltd | Hospitality | 2008 |
| Knutti Limited | Wholesale & retail | 2022 |
| Komserv Ltd | Professional & scientific | 2024 |
| KPS Retail Limited | Wholesale & retail | 2018 |
| KS Take Away Ltd | Hospitality | 2024 |
| KT Project Management Ltd | Professional & scientific | 2019 |
| KW Industrial Painting Ltd | Construction | 2026 |
| L and K Holiday's Ltd | Wholesale & retail | 2025 |
| L C Property Limited | Real estate | 2017 |
| L K Davies Property Investments Ltd | Real estate | 2021 |
| L P R Engineering (GB) Limited | Professional & scientific | 2014 |
| L R Gallone Properties Ltd | Real estate | 2025 |
| L Reece Ltd | Health & social care | 2025 |
| L Smith Management Limited | Administrative & support | 2024 |
| L T Property Limited | Real estate | 2018 |
| L&T Active Properties Ltd | Real estate | 2022 |
| L.D. Renewable Services Limited | Administrative & support | 2023 |
| L.P.B Offshore Ltd | Manufacturing | 2019 |
| L.T.Trewhitt Property Ltd | Hospitality | 2025 |
| Laiken Brickwork Ltd | Construction | 2021 |
| Lakes Service Centre Limited | Wholesale & retail | 2005 |
| Lapoel Travel Ltd | Transport & logistics | 2025 |
| Larksbay View Limited | Real estate | 2018 |
| Lascelles Bond Ltd | Real estate | 2025 |
| LBH Electrical Limited | Professional & scientific | 2015 |
| LBH Management Consultants Ltd | Construction | 2022 |
| Lbkm PUB Group Ltd | Hospitality | 2025 |
| LDE Properties Ltd | Real estate | 2021 |
| Leather Estates Ltd | Construction | 2021 |
| Leather Property Ltd | Real estate | 2024 |
| Lehu Limited | Manufacturing | 2023 |
| LEM Electrical Solutions Ltd | Professional & scientific | 2024 |
| Lemon Grass N Ltd | Hospitality | 2017 |
| Lemon Grass NE Ltd | Hospitality | 2022 |
| Level UP Entertainment Limited | Arts & recreation | 2022 |
| Leven Construction Limited | Construction | 2004 |
| Leweleanor Ltd | Administrative & support | 2013 |
| Lewis Morris Limited | Information & communication | 2023 |
| Lewis Taxation Services Limited | Professional & scientific | 2020 |
| Lewis Thomas Property Investments Limited | Real estate | 2022 |
| LH Engineering Services Ltd | Professional & scientific | 2025 |
| Life Learning & Wellbeing Ltd | Health & social care | 2020 |
| Light of Asia Bangladeshi Cuisine Ltd | Hospitality | 2024 |
| Light of Asia Restaurant Limited | Hospitality | 2019 |
| Lillah Jacobs Limited | Professional & scientific | 2018 |
| Linear Engineering Ltd | Professional & scientific | 2026 |
| Lionheart Marketing Limited | Professional & scientific | 2020 |
| Lisa Hebron Clinic & Academy Ltd | Education | 2026 |
| Little Legs Day Nursery Limited | Education | 2003 |
| Live IT Ventures Ltd | Information & communication | 2006 |
| LJ Property Management Ltd | Real estate | 2022 |
| LJC Architectural Design Ltd | Professional & scientific | 2023 |
| LLL Resell Ltd | Wholesale & retail | 2023 |
| LM Electrical Services (NE) Ltd | Construction | 2021 |
| LM Equine Services Ltd | Agriculture & fishing | 2025 |
| LM Padel Ltd | Arts & recreation | 2026 |
| LMC Wind Ltd | Professional & scientific | 2025 |
| Local Appliance Rentals Ltd | Administrative & support | 2013 |
| Locke Park Cafe Ltd | Hospitality | 2025 |
| Locker's Fish & Chips Limited | Hospitality | 2021 |
| Lockwood Engineering Limited | Professional & scientific | 2017 |
| Loji Properties Limited | Real estate | 2024 |
| Longbeck Discount Tyres Limited | Wholesale & retail | 2025 |
| Longbeck EPC Limited | Professional & scientific | 2020 |
| Longbeck Housing Development Ltd | Real estate | 2019 |
| Longshanks Ltd | Professional & scientific | 2018 |
| Lookship Ltd | Information & communication | 2022 |
| Loud & Clear Hearing Care Ltd | Health & social care | 2022 |
| Lovance Engineering Services Ltd | Professional & scientific | 2024 |
| Lozco Limited | Construction | 2019 |
| LP Auto Solutions Ltd | Wholesale & retail | 2026 |
| LPH (NE) Limited | Information & communication | 2019 |