| Kimmetis Ltd | Administrative & support | 2024 |
| KIN3TIC Performance Limited | Arts & recreation | 2017 |
| Kinch Accommodation Limited | Real estate | 2005 |
| Kinch Electronics Limited | Wholesale & retail | 2004 |
| Kind Events Ltd | Hospitality | 2011 |
| Kindescope Ltd | Information & communication | 2002 |
| Kindmind Counselling Ltd | Health & social care | 2025 |
| Kine Lincoln Limited | Wholesale & retail | 2018 |
| Kinetic Lettings Limited | Real estate | 2022 |
| King & Co. (Lincoln) Limited | Real estate | 2014 |
| King of the Road Coffee Ltd | Hospitality | 2024 |
| Kingdom Caravans Limited | Wholesale & retail | 2019 |
| Kingdom Properties (England) Limited | Construction | 2026 |
| Kingpin Investments and Holdings Ltd | Real estate | 2024 |
| Kingsbury Construction (Lincoln) Limited | Construction | 2025 |
| Kingsley Court (Lincoln) Limited | Real estate | 2005 |
| Kingsmead Design Ltd | Professional & scientific | 2009 |
| Kingsridge Consulting Ltd | Information & communication | 2014 |
| Kingswater - Lindum (Lincoln) Limited | Real estate | 2001 |
| Kingswater-Lindum Limited | Real estate | 1999 |
| Kirkland Estates Limited | Professional & scientific | 2021 |
| Kirks Yard (Branston) Management Company Limited | Real estate | 2017 |
| Kirks Yard Limited | Construction | 2022 |
| Kisimul Group Limited | Education | 1998 |
| KITCHEN66 Limited | Wholesale & retail | 2022 |
| Kitchencraft (Lincoln) Ltd | Construction | 2019 |
| Kitenest Ltd | Manufacturing | 2015 |
| Kittell Limited | Wholesale & retail | 2024 |
| Kixx Lincoln Limited | Education | 2015 |
| Kixx Peterborough Limited | Education | 2019 |
| KJ Steels Ltd | Construction | 2023 |
| KJC Plumbing Solutions Limited | Construction | 2012 |
| KJJ Solutions Ltd | Transport & logistics | 2025 |
| KK Storage Limited | Real estate | 2017 |
| KL Properties (Lincoln) Ltd | Real estate | 2026 |
| KL Property Maintenance Limited | Households | 2014 |
| Klark Properties Ltd | Real estate | 2021 |
| Klassy Nails Ltd | Other services | 2019 |
| Klatto Ltd | Arts & recreation | 2015 |
| Klaudia International Limited | Wholesale & retail | 2024 |
| KLS Security & Electrical Ltd | Construction | 2021 |
| KM Drywall Solutions Ltd | Construction | 2021 |
| KM IP Limited | Real estate | 2019 |
| KMB Ltd | Administrative & support | 1998 |
| KMC Plant Hire Ltd | Administrative & support | 2021 |
| KMD Film Ltd | Information & communication | 2022 |
| KN & S Lewis Ltd | Construction | 2002 |
| KNG Invest Ltd | Administrative & support | 2017 |
| KNG Marketing Limited | Wholesale & retail | 2021 |
| Knight Care Services Ltd | Information & communication | 2024 |
| Knight Wareouse Ltd | Transport & logistics | 2026 |
| Knights Realty Ltd | Real estate | 2022 |
| Know HOW Pubs Ltd | Hospitality | 2026 |
| Knowcarbon Limited | Professional & scientific | 2026 |
| Kodama Consulting Ltd | Professional & scientific | 2014 |
| Kofie Ltd | Wholesale & retail | 2018 |
| Kontent Kreate Ltd | Information & communication | 2026 |
| Kooshen Limited | Manufacturing | 2021 |
| Kotkata Teleradiology Ltd | Health & social care | 2022 |
| Koto Consulting Ltd | Information & communication | 2018 |
| Koushiappi Homes Ltd | Real estate | 2023 |
| KPD Wealth Management Ltd | Financial services | 2021 |
| Kpscd Consulting Ltd | Information & communication | 2012 |
| Kram Contract Cleaning Limited | Administrative & support | 2005 |
| Kranby Properties Holdings LLP | | 2023 |
| Krancon Limited | Information & communication | 2003 |
| Krantz Designs London Ltd | Construction | 2025 |
| Krantz Designs Ltd | Construction | 2015 |
| Krantz Holdings Limited | Financial services | 2022 |
| Krantz Productions Ltd | Information & communication | 2024 |
| Krazy Clearance Limited | Wholesale & retail | 2014 |
| Krazy Kids Lincoln Limited | Arts & recreation | 2023 |
| KRB Healthcare Limited | Health & social care | 2022 |
| KRD Labour Ltd | Construction | 2025 |
| Kre-Anergy Consulting Limited | Real estate | 1998 |
| KRH Cleaning Ltd | Administrative & support | 2014 |
| Krishna House Ltd | Wholesale & retail | 2025 |
| Kristina Homes and Renovations Ltd | Construction | 2026 |
| KRT Thomson Transport Ltd | Transport & logistics | 2025 |
| Krytal Ltd | Information & communication | 2025 |
| Ksat Comms Ltd | Transport & logistics | 2025 |
| Kseauk | Professional & scientific | 2017 |
| KSG Commercial Ltd | Real estate | 2024 |
| KSG Ventures Limited | Manufacturing | 2017 |
| KSR Automotive Scunthorpe Ltd | Manufacturing | 2019 |
| KST Ingredients Ltd | Real estate | 2010 |
| KTF Medic Limited | Health & social care | 2009 |
| Kubaro Ltd | Transport & logistics | 2021 |
| Kubi Foods Ltd | Hospitality | 2025 |
| Kulkarni Healthcare Ltd | Health & social care | 2014 |
| Kulkarni-Nicum Medical Ltd | Health & social care | 2012 |
| Kurnia Licensing Consultants Limited | Professional & scientific | 2012 |
| Kurumabodyworks Ltd | Wholesale & retail | 2024 |
| KVN Business Services Ltd | Professional & scientific | 2016 |
| KW Diamond Ltd | Transport & logistics | 2018 |
| KW Electrical and Contracting Ltd | Construction | 2018 |
| Kyle Barnett Ltd | Health & social care | 2024 |
| KZ Haulage Ltd | Transport & logistics | 2022 |
| L & I Logistics Limited | Transport & logistics | 2023 |
| L & J Lettings Limited | Real estate | 2023 |