| JYG Farriery Limited | Agriculture & fishing | 2011 |
| K & D Recovery Ltd | Wholesale & retail | 2025 |
| K & D Vision Limited | Wholesale & retail | 2010 |
| K & J Construction (York) Ltd | Construction | 2014 |
| K & J Egdell GAS Services Limited | Households | 2004 |
| K & K Jewellers Ltd | Wholesale & retail | 2009 |
| K & L Holdings York Limited | Real estate | 2018 |
| K & M Installations Limited | Other services | 1995 |
| K & M Rail Limited | Construction | 2013 |
| K & N Retail Limited | Real estate | 2009 |
| K Art Ltd | Construction | 2017 |
| K Ball Consultants Limited | Professional & scientific | 2012 |
| K C Solutions Ltd | Professional & scientific | 2024 |
| K Comps Ltd | Wholesale & retail | 2026 |
| K Davis Associates Ltd | Other services | 2015 |
| K K M Holdings Ltd | Financial services | 2022 |
| K K M Management Ltd | Wholesale & retail | 2014 |
| K Lamb Joinery Ltd | Construction | 2021 |
| K Square 2 LLP | | 2015 |
| K Thompson Legal Limited | Administrative & support | 2020 |
| K W Linfoot Limited | Construction | 2016 |
| K W Linfoot Marine Limited | Construction | 2015 |
| K&A IT Ltd | Information & communication | 2011 |
| K&B York Ltd | Real estate | 2025 |
| K&Beastwood Limited | Hospitality | 2025 |
| K&E Jewellery Ltd | Wholesale & retail | 2025 |
| K&J Farming Limited | Agriculture & fishing | 2024 |
| K&R Living Ltd | Real estate | 2022 |
| K&S Property Partners Ltd | Real estate | 2024 |
| K-Tech IT Consulting Ltd | Information & communication | 2022 |
| K. Freeman Holdings Limited | Financial services | 1971 |
| K.Howe Solutions Ltd | Construction | 2023 |
| K.R & M.C Dixon & Sons Limited | Agriculture & fishing | 2023 |
| K.W. Electronics Ltd | Manufacturing | 2025 |
| K1 Shop (York) Ltd | Wholesale & retail | 2025 |
| K2 Management Company Limited | Real estate | 2002 |
| K3V Talent Solutions Ltd | Administrative & support | 2020 |
| KA Consultancy (Global) Ltd | Information & communication | 2010 |
| Kabir Family Law Limited | Professional & scientific | 2018 |
| KAD Group Limited | Wholesale & retail | 2007 |
| Kailash Medical Ltd | Health & social care | 2019 |
| Kaip Property Investments Ltd | Real estate | 2019 |
| Kairos Fitness 1 Ltd | Arts & recreation | 2025 |
| Kaizen Architectural Design Ltd | Professional & scientific | 2014 |
| Kaizen Car Care Ltd | Administrative & support | 2022 |
| Kaizen Combat Arts Ltd | Education | 2017 |
| Kakehashi Ltd | Other services | 2025 |
| Kali Consultancy Ltd | Professional & scientific | 2021 |
| Kalijo Limited | Administrative & support | 2016 |
| Kallika Limited | Wholesale & retail | 2007 |
| Kalpa AI Consulting Ltd | Information & communication | 2025 |
| Kalya Coffee Ltd | Wholesale & retail | 2023 |
| Kama 3 Solutions Limited | Information & communication | 2014 |
| Kanadevia Inova Biogas Home Farm Ltd | Energy | 2013 |
| Kanadevia Inova Biogas Howla HAY Ltd | Energy | 2012 |
| Kanadevia Inova Biogas Washfold Farm Ltd | Energy | 2013 |
| Kanadevia Inova Biogas Westholme Farm Ltd | Energy | 2013 |
| Kanadevia Inova Biogas Wray House Ltd | Energy | 2014 |
| Kanadevia Inova Management Services UK Ltd | Manufacturing | 2015 |
| Kanika Garg Ltd | Health & social care | 2026 |
| KAP Toys Ltd | Wholesale & retail | 2005 |
| Kaptur Creative Ltd | Information & communication | 2017 |
| Kapwa Ltd | Hospitality | 2023 |
| Karbani Limited | Real estate | 2017 |
| Karemel Bespoke Bathrooms Ltd | Professional & scientific | 2019 |
| Karistoft Limited | Construction | 2015 |
| Karst Property Ltd | Real estate | 2023 |
| Karta Kebab Ltd | Hospitality | 2023 |
| Kasa Railway Engineering Limited | Professional & scientific | 2012 |
| Kassurology Ltd | Health & social care | 2022 |
| Kat's Dogs Training Ltd | Agriculture & fishing | 2022 |
| Katherine Elizabeth Personalised Parenting Solutions Ltd | Health & social care | 2020 |
| Kathryn Hanks Recruitment Limited | Professional & scientific | 2013 |
| Katie Hayman Ltd | Real estate | 2023 |
| Katie Lingo Ltd | Professional & scientific | 2020 |
| Katie Sweep Limited | Administrative & support | 2018 |
| Katies House (Acomb) Management Company Limited | Households | 2014 |
| Kato Coaching Ltd | Information & communication | 2023 |
| Katrina Tootell Aesthetics Ltd | Administrative & support | 2021 |
| Kavanti Ltd | Real estate | 2023 |
| KAY Property Services Limited | Real estate | 1999 |
| Kaya D Limited | Other services | 2024 |
| Kayas York Limited | Hospitality | 2017 |
| Kaye Legal Consulting Limited | Professional & scientific | 2020 |
| Kaye Middleton & Co Ltd | Professional & scientific | 2009 |
| Kaye's Hotels Estates Limited | Extraterritorial | 2019 |
| Kayes Investments Ltd | Hospitality | 2022 |
| Kazma Limited | Hospitality | 2023 |
| KB Properties York Ltd | Real estate | 2024 |
| KC Lets Limited | Real estate | 2020 |
| KC Studio Limited | Arts & recreation | 2019 |
| Kc-Tech Distribution Ltd | Wholesale & retail | 2015 |
| KCB Engineering Solutions Limited | Professional & scientific | 2024 |
| Kcdivision Limited | Administrative & support | 2011 |
| KCG Estates Ltd | Other services | 2024 |
| KCO Ltd | Transport & logistics | 2021 |
| KCP Group Ltd | Water & waste | 2025 |
| KD Recoverys Ltd | Administrative & support | 2023 |
| KD Sales Ltd | Wholesale & retail | 2017 |
| KDM Restorations Ltd | Manufacturing | 2020 |