| Head Projects Building Consultancy Ltd | Professional & scientific | 2010 |
| Heads Zone Ltd | Other services | 2020 |
| Headz Zone Limited | Other services | 2026 |
| Healing Hearts & Homes CIC | Education | 2026 |
| Healing House Network | Other services | 2002 |
| Helen's Court (Trowbridge) Limited | Households | 2004 |
| Helix Building Consultancy Limited | Professional & scientific | 2026 |
| Helix Surveyors Limited | Professional & scientific | 2025 |
| Henford Mews Management Limited | Households | 2023 |
| Henley Furnishings Ltd | Manufacturing | 2025 |
| Henley's Cake Company (Trowbridge) Ltd. | Wholesale & retail | 2016 |
| Henrietta Investments Limited | Construction | 1987 |
| Henry Edwards Properties Ltd | Real estate | 2025 |
| Heritage Home Developments Ltd | Real estate | 2020 |
| Heritage Trustees Ltd | Extraterritorial | 2007 |
| Hertz Solutions Ltd | Wholesale & retail | 2019 |
| Hidden and Found Limited | Administrative & support | 2020 |
| Highley Limited | Professional & scientific | 1987 |
| Higzl Ltd | Wholesale & retail | 2025 |
| Hilbury Court Management Company Limited | Professional & scientific | 2021 |
| Hilperton Technical Installations Limited | Construction | 2007 |
| Hinton Services Limited | Wholesale & retail | 2003 |
| Hodya Studios Limited | Arts & recreation | 2026 |
| Holland 71 Limited | Real estate | 2017 |
| Holman and SON Limited | Manufacturing | 2024 |
| Holmesclean Limited | Administrative & support | 2006 |
| Holt Pre-School | Education | 2011 |
| Holy Water Holistics Ltd | Wholesale & retail | 2017 |
| Homefix Services Ltd | Construction | 2016 |
| Homes Nuvo Ltd | Construction | 2022 |
| Horam Custom Build Ltd | Construction | 2023 |
| Hornbeam Engraving Ltd | Professional & scientific | 2026 |
| Host Studio Limited | Other services | 2023 |
| Hridha Limited | Wholesale & retail | 2024 |
| Hubert Lawski Limited | Wholesale & retail | 2016 |
| Hudsons Houses Limited | Real estate | 2017 |
| Hull Kannaki Amman Temple Ltd | Other services | 2026 |
| Human Sense Solutions Ltd | Professional & scientific | 2020 |
| Humber Schoolwear Limited | Real estate | 1988 |
| HUX Hampers Limited | Wholesale & retail | 2014 |
| Hyperbuy Ltd | Wholesale & retail | 2025 |
| I - BAG Properties Ltd | Real estate | 2021 |
| I a Heating Services Limited | Professional & scientific | 2017 |
| IAC Audit and Consultancy Ltd | Professional & scientific | 2015 |
| IAN Anderson Music Limited | Arts & recreation | 1970 |
| IAN Lucas Limited | Construction | 2022 |
| IAN Stokes Consultancy Ltd | Professional & scientific | 2022 |
| Ib&S Ltd | Hospitality | 2021 |
| IBK Interiors Ltd | Construction | 2003 |
| Ice Cool Design Limited | Professional & scientific | 2018 |
| Icehouse Trading Company Limited | Financial services | 1996 |
| ICS Exhibitions Limited | Manufacturing | 2014 |
| Idsuk (Dataconnection) Limited | Manufacturing | 2006 |
| Iexp Solutions Limited | Information & communication | 2025 |
| IF Industries Limited | Wholesale & retail | 2018 |
| IG Sports Coaching Limited | Education | 2017 |
| IGS Independent Limited | Professional & scientific | 2026 |
| IJB Transport Ltd | Transport & logistics | 2018 |
| Ilamera Ltd | Wholesale & retail | 2020 |
| Ilst Property Ltd | Real estate | 2024 |
| IM Consult Service Ltd | Health & social care | 2015 |
| IMJ Properties Ltd | Real estate | 2025 |
| IN Harmony Dental Studio Ltd | Health & social care | 2024 |
| Inbrook Design Ltd | Construction | 2013 |
| Indigo Data Communications Limited | Information & communication | 1998 |
| Indoor Soccer Centres Limited | Arts & recreation | 2025 |
| INFINITY8 Ventures Ltd | Information & communication | 2022 |
| Information EXP Limited | Information & communication | 2019 |
| Inglismanagement Limited | Construction | 2015 |
| Initially Yours Embroiderers Limited | Manufacturing | 1989 |
| Inland Waterways International | Other services | 1994 |
| Inmind Consulting Ltd | Health & social care | 2021 |
| Insight Praxis Limited | Other services | 2025 |
| Integrated Documentation Limited | Professional & scientific | 2009 |
| Interkleen Ltd | Administrative & support | 2011 |
| International Sipp Trustees Limited | Extraterritorial | 2017 |
| Interoception International Ltd | Education | 2025 |
| Investorai Ltd | Information & communication | 2014 |
| Irek Home Improvements Ltd | Construction | 2020 |
| Irvap Ltd | Other services | 2026 |
| Islington Trowbridge Limited | Wholesale & retail | 1979 |
| IT Autonomy Ltd | Information & communication | 2019 |
| Ivcm Heritage Trustees Limited | Extraterritorial | 2016 |
| IVY Leigh Flat Management Company Limited | Households | 1986 |
| J & P Service Centre Limited | Wholesale & retail | 2003 |
| J & R Sparks Ltd | Construction | 2022 |
| J & T Beaven Limited | Wholesale & retail | 1995 |
| J & W Property Ltd | Construction | 2010 |
| J a Sheppard Transport Ltd | Transport & logistics | 2021 |
| J C Mailings Limited | Manufacturing | 1997 |
| J Capital Limited | Financial services | 2012 |
| J D Recycling Limited | Water & waste | 2011 |
| J H Pearce & Co Limited | Wholesale & retail | 2017 |
| J J L F Limited | Wholesale & retail | 2011 |
| J J Rickey Property Ltd | Real estate | 2025 |
| J K Builders & Plant Hire Ltd | Construction | 2018 |
| J K Hamblin Windows & Doors Ltd | Construction | 2026 |
| J Knight Brickwork Limited | Construction | 2008 |
| J P C Infonet Limited | Information & communication | 1994 |
| J Stead Construction Ltd | Construction | 2023 |