| Houghton Manor Management Company Limited | Households | 2009 |
| HRC (Ware) Residents Management Company Limited | Households | 2016 |
| Hummingbird Developments Limited | Professional & scientific | 2014 |
| Hunta IT Services Ltd | Information & communication | 2018 |
| Hunters Meadow Residents Association Limited | Professional & scientific | 2000 |
| Hunters Way (Enfield) Management Company Limited | Households | 2007 |
| Huntingdon (Niab) Management Company Limited | Households | 2010 |
| Hurlocke Fields (North Herts) Management Company Limited | Households | 2022 |
| Hurricane Apparel Ltd | Manufacturing | 2020 |
| Hurst Court (Milford-On-Sea) Limited | Households | 1987 |
| Hutchinson Medical Writing Limited | Administrative & support | 2011 |
| Hutchinson Retail Consulting Limited | Administrative & support | 2013 |
| Huyana Beauty Academy Ltd | Other services | 2025 |
| Hydro Connect Limited | Manufacturing | 2017 |
| Icare Healthcare Limited | Health & social care | 2013 |
| Icdstewart Ltd | Professional & scientific | 2023 |
| Icjr Consultancy Limited | Professional & scientific | 2008 |
| Ideal Produce Limited | Wholesale & retail | 2019 |
| Ignition Ventures Limited | Other services | 2010 |
| Imperial Park (Bristol) Management Company Limited | Households | 2017 |
| Impney Grange Management Company Limited | Households | 2010 |
| Inca Solutions Ltd | Wholesale & retail | 2015 |
| Indigo Apartments Management Company Limited | Real estate | 2003 |
| Industrial Marketing Consultants Ltd | Professional & scientific | 2003 |
| Ingress Park (Greenhithe) Management Limited | Households | 2000 |
| Innovative Solutions for Manufacturing Limited | Professional & scientific | 2016 |
| Inns Parc Amenity Areas Management Company Limited | Households | 2008 |
| Integral Investments Limited | Construction | 1988 |
| Integrated Heating Solutions Ltd | Construction | 2024 |
| Intelligenthelp Limited | Information & communication | 2018 |
| Intrinsic Automotive Limited | Wholesale & retail | 2015 |
| Ionic Box Limited | Information & communication | 2015 |
| Ipcv Ltd | Information & communication | 2019 |
| Isabella Gardens (Chipping Sodbury) Management Company Limited | Households | 2022 |
| Island View Decorators Ltd | Construction | 2026 |
| Ivco Management Company Limited | Households | 1992 |
| Izzy Bizzy Pet Products Ltd | Wholesale & retail | 2021 |
| J ASH Builders Ltd | Construction | 2017 |
| J Harmans Hospitality Ltd | Hospitality | 2023 |
| J Harmans Pubs Limited | Hospitality | 2025 |
| J. F. R. Symons (Electrical) Limited | Construction | 1977 |
| J.D.R Electrical Limited | Extraterritorial | 2015 |
| J.W. Alderson & Co. Limited | Financial services | 1945 |
| Jackfield Mill Residents Association Limited | Households | 1990 |
| Jacmar Court(New Milton)Limited | Households | 1962 |
| Janred Court (Barton-On-Sea) Limited | Households | 1975 |
| Japanese Company Limited | Administrative & support | 2020 |
| Jasmine Gardens Management Company Limited | Construction | 2013 |
| Jejoth Limited | Extraterritorial | 2024 |
| Jenkins House Management Company Limited | Households | 2020 |
| Jenny Palmer Limited | Health & social care | 2002 |
| Jessie Cunnett Consulting Limited | Professional & scientific | 2008 |
| JET Airplane Ltd | Information & communication | 2025 |
| JJ Southsea Limited | Real estate | 2016 |
| JLR Hospitality Ltd | Hospitality | 2023 |
| Jobs Midco 2 Limited | Financial services | 2022 |
| Joby Properties Limited | Real estate | 2025 |
| JON Lever Plumbing and Heating Limited | Other services | 2018 |
| JPN Networks Limited | Construction | 2017 |
| Jpsc Ltd | Professional & scientific | 2013 |
| JRB Residential Surveyors Ltd | Construction | 2024 |
| Jubilee Green (Charlton Marshall) Management Company Limited | Households | 2023 |
| Judith Gardens (Sawtry) Managing Company Limited | Professional & scientific | 2020 |
| Julsa Limited | Hospitality | 2024 |
| Juncker Marine Limited | Manufacturing | 2022 |
| Junction (Southend) Management Company Limited | Households | 2008 |
| Jupiter (Phase 1) Management Company Limited | Households | 2002 |
| Jupiter (Phase 2) Management Company Limited | Households | 2003 |
| Just Beespoke IT Limited | Real estate | 2021 |
| Just Mini UK Limited | Wholesale & retail | 2024 |
| Justin Dempster Ltd | Construction | 2018 |
| Jwibc Limited | Other services | 2017 |
| Jynx Piercing Ltd | Other services | 2025 |
| K Reach (EA) Management Company Limited | Households | 2009 |
| K S Asset Management Limited | Real estate | 2021 |
| K.A. Terry Limited | Information & communication | 2000 |
| Kaleidoscape Landscaping Limited | Administrative & support | 2010 |
| Kamtee Ltd | Professional & scientific | 2022 |
| Katie Palmer Hair Ltd | Other services | 2018 |
| KAZ White Limited | Professional & scientific | 2016 |
| KC Estate Management Limited | Households | 2001 |
| KCG Scaffold Services Limited | Construction | 2012 |
| Kcjcdistributions Ltd | Wholesale & retail | 2026 |
| Keel Property Developers Limited | Real estate | 2006 |
| Keeper's Chase (Audenshaw) Management Company Limited | Households | 2007 |
| Keffen Construction Ltd | Construction | 2017 |
| Keffen Plant Hire Ltd | Administrative & support | 2011 |
| Keffen Properties Ltd | Real estate | 2020 |
| Kelrob Ltd | Professional & scientific | 2022 |
| Kelvedon (Colchester) Management Company Limited | Households | 2022 |
| Kemp IT Services Limited | Information & communication | 2020 |
| Kempsey Mead Residents Management Company Limited | Construction | 2015 |
| Kempton HR Consultancy Ltd | Professional & scientific | 2021 |
| Kendell Management Limited | Professional & scientific | 2019 |
| Kenilworth Close Property Management Limited | Households | 1967 |
| Kensington Park Management Company Limited | Households | 2008 |
| Kent Particles Ltd | Agriculture & fishing | 2024 |
| Kernick Gate Management Company Limited | Households | 2013 |
| Kestrel Ridge at Sandy Management Company Limited | Households | 2014 |
| KEW Bridge Management Company Limited | Households | 2021 |