| Just Holding Things Ltd | Wholesale & retail | 2022 |
| Justin Swales Ltd | Construction | 2005 |
| Justmerc Limited | Financial services | 2014 |
| JW Change Consultancy Limited | Professional & scientific | 2015 |
| JWH Marketing Ltd | Professional & scientific | 2019 |
| JWS Construction (Yorkshire) Limited | Construction | 2024 |
| K Dann Asset Finance Limited | Financial services | 2003 |
| K Newton Haulage Limited | Transport & logistics | 2009 |
| K P Motorsport Ltd | Wholesale & retail | 2005 |
| K W I Holdings Limited | Real estate | 2024 |
| K.Ducova Ltd | Health & social care | 2018 |
| K9 Stars Ltd | Education | 2024 |
| Kada Training Academy CIC | Administrative & support | 2026 |
| KAL Topco Limited | Financial services | 2025 |
| Kapow Gifts Ltd | Wholesale & retail | 2016 |
| Karibo Properties Limited | Households | 2002 |
| Karl Barker Bespoke Limited | Manufacturing | 2022 |
| Karoo Equine Ltd | Manufacturing | 2019 |
| KB Acupuncture Ltd | Professional & scientific | 2023 |
| KDR Homes Ltd | Real estate | 2024 |
| Keel Innovative Digital (Hull) Limited | Other services | 2017 |
| Keeper's Medical Consulting Limited | Health & social care | 2022 |
| Keith Warren Installations Limited | Agriculture & fishing | 2019 |
| Kelk Farming Co. Ltd | Agriculture & fishing | 2011 |
| Kelo Engineering Ltd | Professional & scientific | 2019 |
| Kennedy Farming Ltd | Agriculture & fishing | 2017 |
| Kentech Software Solutions Limited | Administrative & support | 2017 |
| Keystone Surveyors Ltd | Professional & scientific | 2019 |
| KGL Business Solutions Ltd | Administrative & support | 2019 |
| Kingfisher Lakes Ltd | Hospitality | 2025 |
| Kingsley Research Limited | Information & communication | 1988 |
| Kingston Ice Hockey Club Limited | Arts & recreation | 2015 |
| Kingstown Associates (Holdings) Limited | Professional & scientific | 2015 |
| Kingstown Associates Limited | Wholesale & retail | 2008 |
| Kirkburn Cars Auto Centre Ltd | Wholesale & retail | 2025 |
| Kirkby Foods Limited | Manufacturing | 2026 |
| Kirsty Edmond Ltd | Professional & scientific | 2021 |
| KIS Financial Limited | Financial services | 2026 |
| Kitchen Design Solutions Ltd | Construction | 2022 |
| Kitts Motor Engineers Ltd | Wholesale & retail | 2020 |
| Klaafe Limited | Administrative & support | 2016 |
| KMR Lettings Ltd | Real estate | 2025 |
| KMR Sewing Ltd | Wholesale & retail | 2025 |
| KMW Catching Services Limited | Agriculture & fishing | 2026 |
| KNH Trading Ltd | Wholesale & retail | 2019 |
| KNT Hire & Sales Limited | Administrative & support | 2008 |
| Koala Heat Metering Ltd | Professional & scientific | 2026 |
| KP Cattery Limited | Other services | 2018 |
| KP Consult Ltd | Professional & scientific | 2016 |
| Kurdish Barbers 11 Ltd | Other services | 2023 |
| KWI Buildings Ltd | Manufacturing | 2024 |
| Kyle Commercial Structure Ltd | Construction | 2025 |
| L & P Electrical Ltd | Construction | 2018 |
| L and G Agri Ltd | Agriculture & fishing | 2024 |
| L T H Recycling Limited | Water & waste | 2022 |
| L&N Renovation and Development Ltd | Real estate | 2026 |
| L&P Housing Solution Ltd | Real estate | 2024 |
| L.H.Sleightholme Limited | Construction | 1973 |
| L.V. Tomlinson and SON Limited | Manufacturing | 1977 |
| L.V. Tomlinson Holdings Limited | Financial services | 2018 |
| Lakeside Labradoodles Ltd | Wholesale & retail | 2023 |
| Lamb Property Solutions Limited | Real estate | 2025 |
| Lampard Creative Holdings Ltd | Wholesale & retail | 2026 |
| Land Network Limited | Water & waste | 1998 |
| Landing Farm Estates Limited | Agriculture & fishing | 2012 |
| Langtoft Pizza Ltd | Hospitality | 2026 |
| Laurel Park Lissett Ltd | Hospitality | 2023 |
| Laurel Vines, Vineyard & Winery Limited | Manufacturing | 2013 |
| LB Automotive (Driffield) Ltd | Wholesale & retail | 2026 |
| Lbradley Holdings Limited | Administrative & support | 2021 |
| LC Nutrition Limited | Health & social care | 2023 |
| LC Virtual PA Services Ltd | Administrative & support | 2023 |
| Lclm Limited | Construction | 2024 |
| LD Farming Ltd | Agriculture & fishing | 2023 |
| LDK Solutions Ltd | Professional & scientific | 2024 |
| Leadexec Ltd | Professional & scientific | 2023 |
| Legends & Rebels Ltd | Other services | 2025 |
| Legrams Properties 1997 Limited | Households | 1997 |
| LEO Construction (UK) Limited | Professional & scientific | 2004 |
| Less & More Limited | Hospitality | 2025 |
| Lewis Garner Consulting Limited | Administrative & support | 2012 |
| Liberty Serviced Accommodation UK Limited | Real estate | 2018 |
| Lifeline and Logistics Ltd | Transport & logistics | 2025 |
| Lift on US Ltd | Administrative & support | 2021 |
| Lighthouse Road Glamping Limited | Arts & recreation | 2019 |
| Lillys P & H Ltd | Construction | 2021 |
| Limitless Campers Ltd | Manufacturing | 2024 |
| Lincoln Commercial Developments Limited | Manufacturing | 2003 |
| Lincoln Laundry Limited | Other services | 2009 |
| Lincolnshire Interiors Limited | Wholesale & retail | 2001 |
| Liquid (UK) Limited | Professional & scientific | 2008 |
| Lite Properties Limited | Real estate | 2021 |
| Little Bee's Day Nursery & Pre-School Limited | Health & social care | 2018 |
| Little Hamar Farm Company | Agriculture & fishing | 2003 |
| Little Jims Limited | Real estate | 2022 |
| Little Park Farm Limited | Professional & scientific | 2011 |
| Little Rascals (Yorkshire) Limited | Wholesale & retail | 2009 |
| Little Robins' Day Nursery Nafferton Ltd | Health & social care | 2025 |
| Little Wren Services Limited | Administrative & support | 2021 |
| Littleseed Farms Ltd | Manufacturing | 2018 |