| Hornbridge Limited | Construction | 2025 |
| Hornchurch Breakfast Bar Ltd | Hospitality | 2018 |
| Hornchurch Construction Ltd | Administrative & support | 2014 |
| Hornchurch Fish & Chips Limited | Hospitality | 2017 |
| Hornchurch Food & Wine Ltd | Wholesale & retail | 2025 |
| Hornchurch Heating Limited | Other services | 2018 |
| Hornchurch Jewellers Ltd | Other services | 2016 |
| Hornchurch Marquees Corporate Events Ltd | Hospitality | 2024 |
| Hornchurch Marquees Ltd | Administrative & support | 2024 |
| Hornchurch Phones and Accessories Ltd | Wholesale & retail | 2019 |
| Hornchurch Productions Limited | Arts & recreation | 2015 |
| Hornchurch Properties Ltd | Real estate | 2013 |
| Hornchurch Spice HUT Ltd | Hospitality | 2025 |
| Hornchurch Tyres Ltd | Wholesale & retail | 2022 |
| Horngood Limited | Real estate | 1984 |
| Horsley Management Ltd | Professional & scientific | 2024 |
| Hosbro Limited | Real estate | 2021 |
| Hospitality Hornchurch Ltd | Hospitality | 2024 |
| Hossain and Co Properties Ltd | Real estate | 2025 |
| Hot Flame Limited | Construction | 2010 |
| Hotaru Ltd | Information & communication | 2021 |
| Hotc Books Ltd | Wholesale & retail | 2021 |
| Hotel & Leisure Interiors Ltd | Construction | 2007 |
| Hotel Connections Limited | Hospitality | 1978 |
| Houlihan Safety Services Limited | Health & social care | 2011 |
| House 2 Home Mortgage Solutions Ltd | Financial services | 2020 |
| House Independent Financial Advisers Limited | Financial services | 2017 |
| House of Birds Ltd | Real estate | 2024 |
| House of Koranteng Ltd | Professional & scientific | 2021 |
| House of Lambert Ltd | Professional & scientific | 2020 |
| House of Latyva Ltd | Wholesale & retail | 2024 |
| House of Sky Ltd | Wholesale & retail | 2025 |
| House of Slay Limited | Wholesale & retail | 2025 |
| House Service Ltd | Construction | 2015 |
| Housescapes Ltd | Construction | 2021 |
| Howard Harrison Limited | Professional & scientific | 2020 |
| Howard Micropubs Limited | Hospitality | 2015 |
| Howards Hounds Ltd | Other services | 2025 |
| Howe Coach Hire Ltd | Transport & logistics | 2020 |
| HP Enterprises Limited | Information & communication | 2025 |
| HR & RS Properties Limited | Real estate | 2020 |
| HR and RS Investments Limited | Real estate | 2015 |
| HR Recording Studios Limited | Information & communication | 2022 |
| Hriss Skincare and Aesthetics Ltd | Other services | 2024 |
| HRS Residential Estates Limited | Real estate | 2024 |
| HS 2024 Investments Ltd | Real estate | 2024 |
| HS Carpets and Flooring Ltd | Construction | 2019 |
| HS Developments E1 LLP | | 2020 |
| HS Fish & Shish Ltd | Hospitality | 2025 |
| HS Solutions Upminster Limited | Information & communication | 2013 |
| HSA Trusted Express Service Ltd | Administrative & support | 2023 |
| HSY Accountants Ltd | Professional & scientific | 2011 |
| HSY Investment London Ltd | Real estate | 2020 |
| HT Asian Ltd | Professional & scientific | 2022 |
| HTP Holdings Ltd | Financial services | 2020 |
| Htst Investment Ltd | Real estate | 2020 |
| Hughes Plumbing & Heating Essex Limited | Construction | 2016 |
| Hulk Heating Solutions Ltd | Construction | 2026 |
| Humble Beninging Ltd | Hospitality | 2021 |
| Hundal Dental Limited | Health & social care | 2019 |
| Hundal Orthopaedics Limited | Health & social care | 2011 |
| Hunt Properties Limited | Real estate | 2025 |
| Hurleys Construction Ltd | Construction | 2025 |
| Hurst Associates (Essex) Limited | Professional & scientific | 2019 |
| Hutton Metal Recycling Ltd | Water & waste | 2017 |
| HW BTL Ltd | Real estate | 2025 |
| HWQ Electrical Ltd | Construction | 2024 |
| Hybrid Training and Consulting Limited | Extraterritorial | 2013 |
| Hylands Plumbing & Heating Ltd | Construction | 2025 |
| Hylands Trading Ltd | Information & communication | 2026 |
| I & K Co Ltd | Hospitality | 2026 |
| I P H Limited | Construction | 2013 |
| I&M Real Estate Holdings Ltd | Real estate | 2025 |
| I. Foster & Sons Limited | Manufacturing | 1994 |
| I.C. Goossens Limited | Health & social care | 2007 |
| IA Endodontics Ltd | Health & social care | 2025 |
| Ia-Foundation | Education | 2019 |
| IAN Bartlett Commentaries Limited | Arts & recreation | 2002 |
| Ibiza Media Services Limited | Professional & scientific | 2018 |
| IBN Tayimiyyah Ltd | Health & social care | 2021 |
| IBO Barbers RM12 Ltd | Other services | 2024 |
| Ibto Security Ltd | Administrative & support | 2022 |
| Ibuildpro Financial Holdco Limited | Financial services | 2026 |
| Ibuildpro Holdings Limited | Financial services | 2019 |
| Icanyoucantoo CIC | Health & social care | 2019 |
| Ice Cream Galore Ltd | Hospitality | 2025 |
| Ice Menswear Limited | Wholesale & retail | 2006 |
| Iced Carbon Limited | Information & communication | 1995 |
| Icl-Projects Ltd | Professional & scientific | 2022 |
| Icon Waste Services Limited | Wholesale & retail | 2019 |
| Icxt Group Limited | Administrative & support | 2024 |
| Ideal Fireplaces Limited | Manufacturing | 2016 |
| Idix Consulting Limited | Information & communication | 2018 |
| Idix Properties Limited | Real estate | 2022 |
| Idts Limited | Information & communication | 2024 |
| IF City Limited | Construction | 2015 |
| Ifymax Business Solutions Limited | Other services | 2016 |
| IG Caring Pathways Ltd | Health & social care | 2025 |
| Ignio Hub CIC | Education | 2025 |
| Ignis Consulting Services Ltd | Professional & scientific | 2020 |