| JT Capital Investments Ltd | Real estate | 2025 |
| Just BE One Ltd | Health & social care | 2020 |
| JYM Hadfield Ltd | Hospitality | 2015 |
| K & M Control Systems Limited | Professional & scientific | 1986 |
| K V Cars Ltd | Wholesale & retail | 2012 |
| Kabetex Limited | Manufacturing | 1975 |
| Kaiser Media Limited | Information & communication | 2016 |
| Kaizen Accountancy Services Limited | Professional & scientific | 2021 |
| Kaizen Peak Investments Ltd | Real estate | 2026 |
| Karmar Partnership Ltd | Professional & scientific | 2025 |
| Karrma Homeware & Lifestyle Ltd | Wholesale & retail | 2019 |
| Kaslu Ltd | Professional & scientific | 2024 |
| Kate Thorpe Fitness Ltd | Arts & recreation | 2024 |
| KAW Holdings Ltd | Financial services | 2019 |
| Kaya Care Ltd | Health & social care | 2024 |
| Kefi Social Ltd | Hospitality | 2025 |
| Kennedy PUB Co Limited | Hospitality | 2024 |
| Kerry Glossop Ltd | Hospitality | 2024 |
| Key Stone Consulting (NW) Limited | Professional & scientific | 2026 |
| Keystone Black Ltd | Professional & scientific | 2024 |
| Kinder Cottages Limited | Professional & scientific | 2011 |
| Kinderview Children's Day Nursery Ltd | Education | 2015 |
| Kingsley Blenkhorn Limited | Construction | 1990 |
| Kingston House Management (Glossop) Limited | Administrative & support | 2012 |
| Kirtleway Ltd | Hospitality | 2012 |
| KJB Capital Ltd | Financial services | 2025 |
| Klpj Properties Limited | Real estate | 2021 |
| KM Human Resources Ltd | Administrative & support | 2023 |
| KPJ Group Limited | Administrative & support | 1985 |
| KRS (NW) Limited | Real estate | 2019 |
| Krwh Limited | Health & social care | 2024 |
| Kudos Drinks Ltd | Wholesale & retail | 2013 |
| KV Services & Parts Ltd | Wholesale & retail | 2022 |
| KVB Windows Ltd | Construction | 2015 |
| KZH Foods Ltd | Wholesale & retail | 2025 |
| L G Groundworks Limited | Administrative & support | 2014 |
| L J Dunwoody Construction Limited | Construction | 2007 |
| LA G Group Limited | Construction | 2025 |
| LA Garage Conversions Limited | Construction | 2022 |
| Lale Homes UK Ltd | Hospitality | 2019 |
| Lammers Design Ltd | Manufacturing | 2014 |
| Lamp Light Technologies Limited | Information & communication | 2025 |
| Lancashire GAS Limited | Wholesale & retail | 2020 |
| Lancashire GAS Morecambe & Heysham Limited | Wholesale & retail | 2022 |
| Landcare Management Limited | Administrative & support | 2012 |
| Lansdowne Roofing Supplies Limited | Water & waste | 1990 |
| Lansley Tech Solutions Ltd | Information & communication | 2025 |
| Lawn MAN (Exeter) Ltd | Other services | 2010 |
| LC Glossop Ltd | Hospitality | 2024 |
| LCH Design UK Limited | Other services | 2006 |
| LDL Components Ltd | Administrative & support | 2009 |
| LDL Holdings Limited | Financial services | 2017 |
| LDO Properties Limited | Real estate | 2018 |
| Leading Edge Hair and Beauty Ltd | Other services | 2010 |
| Lean LAB Training Ltd | Arts & recreation | 2026 |
| Ledon Motorsport Services Ltd | Wholesale & retail | 2014 |
| Ledretail Ltd | Wholesale & retail | 2015 |
| LEE and LEE Partnership Ltd | Wholesale & retail | 2015 |
| Leon Martyn Limited | Wholesale & retail | 2019 |
| Leonie Williams Therapy Limited | Health & social care | 2025 |
| Letz Easy Limited | Real estate | 2016 |
| LG Cylinders Limited | Wholesale & retail | 2025 |
| Lhasa Consulting Ltd | Administrative & support | 2025 |
| Libelle Investments Limited | Real estate | 2021 |
| Lightside Mortgage Services Limited | Financial services | 2011 |
| Limefield Design Solutions Ltd | Professional & scientific | 2024 |
| Lincs Drywall Limited | Construction | 2005 |
| Lindsey ANN Ltd | Health & social care | 2022 |
| Linear Vintage Ltd | Wholesale & retail | 2020 |
| Liquidity Growth Limited | Hospitality | 2025 |
| Liquidity Securities Limited | Real estate | 2025 |
| LIT Group Ltd | Construction | 2026 |
| Little Bookkeeper Ltd | Professional & scientific | 2026 |
| Little GEM Experts Limited | Information & communication | 2024 |
| Little Web Creations Ltd | Professional & scientific | 2025 |
| Littlemissclean Ltd | Administrative & support | 2025 |
| Littlemoor Campbell Limited | Other services | 2016 |
| Living Roofs Ltd | Construction | 2024 |
| LMW Services LLP | | 2022 |
| Local Creative LAB CIC | Arts & recreation | 2024 |
| Local Creative Project Limited | Arts & recreation | 2021 |
| Logan Jacobs Limited | Construction | 2018 |
| Lomas and Company Accountants Limited | Professional & scientific | 1998 |
| Lomas and Company Wealth Management LLP | | 2009 |
| Lomas Equestrian Ltd | Wholesale & retail | 2024 |
| Lomas Foods Limited | Wholesale & retail | 2003 |
| Lomas Makin Schofield Developments Limited | Construction | 2002 |
| London House Stoke Limited | Households | 2025 |
| Longmark Tax Conferences Limited | Professional & scientific | 2005 |
| Lost Island Labs Ltd | Information & communication | 2011 |
| Lower Fold (Marple Bridge) Management Company Limited | Other services | 2013 |
| Loxley Homes Bluebell Mews Management Company Limited | Real estate | 2021 |
| Loyal Hounds School for Dogs Ltd | Professional & scientific | 2019 |
| LP Hospitality Limited | Hospitality | 2024 |
| LP SD One Hundred Forty Five Limited | Wholesale & retail | 2023 |
| Lucentia Ltd | Manufacturing | 2010 |
| LUCILY1419 Ltd | Hospitality | 2020 |
| Lush Nails and Beauty Limited | Other services | 2017 |
| LWF Group Limited | Wholesale & retail | 2015 |
| LXS Properties Limited | Real estate | 2022 |