| Instapay Holdings Ltd | Other services | 2019 |
| Integrated Business Development (UK) Limited | Professional & scientific | 2003 |
| Invacar Limited | Wholesale & retail | 2022 |
| Invixa Ltd | Information & communication | 2026 |
| IO Education Services Limited | Education | 2021 |
| Iracroft Limited | Manufacturing | 1972 |
| IRJ Holdings Limited | Real estate | 2020 |
| Isometric Solutions Limited | Information & communication | 2024 |
| Issy Rush-Jansen Ltd | Arts & recreation | 2015 |
| Itchen Construction Limited | Construction | 2021 |
| Iter Group Limited | Construction | 2026 |
| Ivydore Holdings Limited | Real estate | 2018 |
| Iwerne Minster Management Company (2006) Limited | Households | 2006 |
| J & J Electrical (South) Ltd | Construction | 2021 |
| J & M Booze (Dorset) Limited | Wholesale & retail | 2013 |
| J C Hardy Electrical Ltd | Construction | 2022 |
| J L QS Services Ltd | Professional & scientific | 2025 |
| J M Commercials & Sons Ltd | Wholesale & retail | 2022 |
| J Strong Enterprises Limited | Extraterritorial | 2016 |
| J T Corfe Limited | Hospitality | 2016 |
| J. Burgess and Associates Limited | Professional & scientific | 1987 |
| J.A. Coombes Limited | Construction | 2003 |
| J.A.M. Marketing Limited | Wholesale & retail | 1998 |
| J.Coast Construction Ltd. | Construction | 2012 |
| J.M97 Limited | Wholesale & retail | 2025 |
| J.R. & S.R. Webber Limited | Agriculture & fishing | 1964 |
| Jade Campbell-Bell Ltd | Health & social care | 2019 |
| Jaja Consultancy Limited | Professional & scientific | 2025 |
| James Babb Workshops Ltd | Manufacturing | 2015 |
| Jamie Gordon Limited | Professional & scientific | 2013 |
| Jane Shaw Sculpture Limited | Arts & recreation | 2023 |
| JBM Associates Ltd | Professional & scientific | 2026 |
| JD IMS Ltd | Extraterritorial | 2023 |
| JDG Structural Steel Limited | Construction | 1999 |
| JDM Island Properties Limited | Real estate | 2015 |
| Jedfield Limited | Professional & scientific | 1984 |
| Jemstar Pubs Ltd | Hospitality | 2025 |
| Jenkin Hughes Ltd | Professional & scientific | 2013 |
| Jennings Organs Ltd | Manufacturing | 2024 |
| Jerrys JFC Ltd | Hospitality | 2023 |
| Jerrys Steak House Ltd | Hospitality | 2023 |
| Jerry’S Hospitality Ltd | Hospitality | 2022 |
| JF Jointing Limited | Construction | 2025 |
| Jgsales Ltd | Wholesale & retail | 2025 |
| Jibworx Ltd | Arts & recreation | 2022 |
| JK Care Assessments Ltd | Health & social care | 2025 |
| JK NDT Services Ltd | Professional & scientific | 2022 |
| JK Property Management Services Ltd | Households | 2026 |
| JO Blair HR Consultancy Ltd | Professional & scientific | 2014 |
| JP Landscaping & Fencing Ltd | Administrative & support | 2020 |
| JRH Marine Ltd | Professional & scientific | 2021 |
| Jurassic Coast Mushrooms Ltd | Agriculture & fishing | 2024 |
| K E M Buck Ltd | Professional & scientific | 2017 |
| K John Limited | Hospitality | 2008 |
| K-Tech (GB) Limited | Wholesale & retail | 2011 |
| Kabi Retails Ltd | Wholesale & retail | 2025 |
| KAI & Co Investments Ltd | Real estate | 2016 |
| Kalaam Media Ltd | Information & communication | 2008 |
| Kalaido Web Ltd | Information & communication | 2025 |
| Kasteel Collection Limited | Hospitality | 2018 |
| KAT Miles Coaching Ltd | Health & social care | 2020 |
| Kathryn Court (Charlton Marshall) Residents Limited | Households | 2021 |
| Keeda Property Investment Limited | Real estate | 2025 |
| Keeda Services Ltd | Construction | 2019 |
| Kernon Kelleher Solicitors Limited | Professional & scientific | 2007 |
| Keystonexl Limited | Professional & scientific | 2015 |
| KG Structures Limited | Professional & scientific | 2009 |
| Kieron Howard Limited | Information & communication | 2018 |
| Kingsbere Kitchen Ltd | Hospitality | 2021 |
| Kingston Barnyard Management Company Limited | Households | 2002 |
| Knees UP Healthy Living Ltd | Health & social care | 2008 |
| Know the Truth Ltd | Education | 2023 |
| Kristow Ltd | Professional & scientific | 2024 |
| Kurdish Barbers (Dorset) Ltd | Other services | 2024 |
| L&D Designs Limited | Administrative & support | 2014 |
| LA Contractors Ltd | Construction | 2025 |
| Lady H Holdings Ltd | Wholesale & retail | 2019 |
| Langers & SON Limited | Administrative & support | 2005 |
| Langton Garage Ltd | Wholesale & retail | 2008 |
| Langton Stables Limited | Households | 1987 |
| Latham Park Developments Limited | Construction | 1988 |
| Lcli 1966 Limited | Professional & scientific | 2015 |
| Leopard Oceanic Limited | Manufacturing | 2004 |
| Lerwill Hadland Limited | Professional & scientific | 2013 |
| Lets Organisation Limited | Health & social care | 2025 |
| Lewick Ltd | Financial services | 2019 |
| Lewis Vehicle Services Ltd | Wholesale & retail | 2023 |
| LEX Mcmillan Architects Ltd | Professional & scientific | 2010 |
| Lifesignsmonitoringsolutions (Lsms) Limited | Manufacturing | 2011 |
| Lift TEC Crane Services Limited | Construction | 2015 |
| Lightning UX Ltd | Professional & scientific | 2023 |
| Lightride Ltd | Information & communication | 2009 |
| Links Developments & Design Limited | Wholesale & retail | 2018 |
| Little Blue Lobster Limited | Real estate | 2021 |
| Little Glebe Houghton Management Limited | Water & waste | 1987 |
| Littleport Holdings Limited | Financial services | 2015 |
| Littleton Park Farming LLP | | 2023 |
| Littletowns Management and Maintainance Ltd | Real estate | 2022 |
| Livingbeer . COM Limited | Wholesale & retail | 2003 |
| Livra Consultancy Limited | Information & communication | 2020 |