| Hyde Contractors Limited | Construction | 2019 |
| Hydepark Minimarket Doncaster Limited | Wholesale & retail | 2024 |
| Hydepark Store Limited | Wholesale & retail | 2026 |
| Hydrastore Limited | Manufacturing | 1989 |
| Hydro Global Engineering Services Limited | Professional & scientific | 2014 |
| Hygge Cottage Holidays Ltd | Hospitality | 2024 |
| Hygge House Nursery Ltd | Education | 2024 |
| Hykeham O & M Services Limited | Water & waste | 2010 |
| Hyper Fast Logistics UK Ltd | Transport & logistics | 2023 |
| Hyper Hosting Services Ltd | Other services | 2009 |
| Hypnotherapy 23 Ltd | Health & social care | 2026 |
| Hysyscare Limited | Manufacturing | 2017 |
| Hysysco Ltd. | Manufacturing | 2013 |
| HZH Trading & Construction Ltd | Other services | 2017 |
| I AM Able 2 Ltd | Real estate | 2023 |
| I AM the Renovation Ltd | Wholesale & retail | 2020 |
| I C Foods Ltd | Wholesale & retail | 2021 |
| I Call Limited | Administrative & support | 2016 |
| I CAN Save a Life Ltd | Education | 2022 |
| I D (E&I) Site Services Limited | Professional & scientific | 2016 |
| I E Willey Limited | Construction | 1987 |
| I J Kellam Limited | Health & social care | 2011 |
| I Never Knew That Ltd | Arts & recreation | 2006 |
| I P V Solutions Ltd | Transport & logistics | 2009 |
| I P W Joinery Limited | Construction | 2008 |
| I Refurb Mobiles Ltd | Other services | 2025 |
| I SEE YOU and YOU ARE Perfect Ltd | Wholesale & retail | 2025 |
| I Services Doncaster Limited | Other services | 2024 |
| I T S Asbestos Solutions Ltd | Professional & scientific | 2020 |
| I Tigress Ltd | Arts & recreation | 2022 |
| I&A Building Services Ltd | Administrative & support | 2016 |
| I&A Letting and Property Management Ltd | Real estate | 2026 |
| I&M Clean Limited | Administrative & support | 2021 |
| I'M Bread Limited | Manufacturing | 2025 |
| I-5 Football Academy Ltd | Education | 2024 |
| I-De-Builder Ltd | Construction | 2018 |
| I-Drains Limited | Water & waste | 2013 |
| I-Pegasus Community Interest Company | Education | 2017 |
| I-Tech Engineering Limited | Manufacturing | 2022 |
| I.R. Sarjantson Limited | Wholesale & retail | 1978 |
| I.Top Communications Ltd | Administrative & support | 2013 |
| IAA UK Auctions Holdings Limited | Wholesale & retail | 2019 |
| IAA UK Auctions Limited | Wholesale & retail | 2019 |
| IAB Consulting Limited | Administrative & support | 2021 |
| Iaca Limited | Financial services | 2022 |
| Iacob Ionut Ltd | Hospitality | 2021 |
| IAH Services Limited | Administrative & support | 2015 |
| IAN Ashley Scott Ltd | Extraterritorial | 2025 |
| IAN Blessed and Co, Independent Financial Consultants Ltd | Financial services | 1986 |
| IAN Bramall Lettings Ltd | Administrative & support | 2008 |
| IAN Clark Joinery Limited | Manufacturing | 2010 |
| IAN Fenn Consulting Ltd | Professional & scientific | 2020 |
| Iauha Ltd | Wholesale & retail | 2025 |
| Iavram Ltd | Transport & logistics | 2024 |
| IBB International Services Ltd | Transport & logistics | 2020 |
| IBB Properties Ltd | Construction | 2022 |
| Ibexx Flooring Group Ltd | Manufacturing | 2024 |
| Ibiza Market Ltd | Wholesale & retail | 2024 |
| Ibos Pizza Limited | Hospitality | 2026 |
| Ibou Group Ltd | Professional & scientific | 2025 |
| Ibse Business Ltd | Administrative & support | 2019 |
| IC Asset Management Limited | Real estate | 2024 |
| IC Auto Repairs and Servicing Ltd | Wholesale & retail | 2025 |
| ICA Courier Ltd | Transport & logistics | 2025 |
| Ice Cream Direct (Central) Limited | Manufacturing | 2012 |
| Ice Cream Room Ltd | Hospitality | 2018 |
| Ice Spot Limited | Hospitality | 2019 |
| Ice-Cream Direct (UK) Limited | Wholesale & retail | 1995 |
| Iceberg Entertainment Ltd | Hospitality | 2024 |
| Icebreaker Studio Limited | Information & communication | 2018 |
| Icebubble Limited | Information & communication | 2009 |
| ICF Express Ltd | Transport & logistics | 2023 |
| Ichimpharma Limited | Wholesale & retail | 2011 |
| ICL Group Ltd | Transport & logistics | 2016 |
| ICM Interiors Ltd | Construction | 2014 |
| ICM Transport Ltd | Transport & logistics | 2025 |
| Icon Housing Limited | Real estate | 2017 |
| Iconic Hospitality Limited | Other services | 2022 |
| Iconish Ltd. | Wholesale & retail | 2023 |
| ICT - Security Ltd | Professional & scientific | 2007 |
| ICT Black Limited | Information & communication | 2022 |
| ICU 2 Limited | Construction | 2010 |
| ICU2 Security Limited | Construction | 2008 |
| ID Auto Garage Ltd | Wholesale & retail | 2026 |
| ID Creative Homes Ltd | Construction | 2025 |
| ID OIL Tools UK Ltd | Mining & quarrying | 2022 |
| Id-Entity Visual Design Ltd | Professional & scientific | 2025 |
| Idaa Group Limited | Construction | 2021 |
| Idblast Limited | Professional & scientific | 2008 |
| IDC Rail Projects Limited | Construction | 2010 |
| Idea Icon Limited | Administrative & support | 2005 |
| Ideal Electrical & Security Services Ltd | Construction | 2020 |
| Ideal Energy Ltd | Professional & scientific | 2019 |
| Ideal Estates and Property Management Ltd | Real estate | 2010 |
| Ideal Financial Management Holdings Limited | Financial services | 2020 |
| Ideal Financial Management Limited | Financial services | 2001 |
| Ideal Gifts & Cards Ltd | Wholesale & retail | 2015 |
| Ideliver Ltd | Construction | 2024 |
| IDF Property Solutions Limited | Construction | 2023 |
| Idle Crane Limited | Information & communication | 2012 |