| Harris Strategic Land (Docks) Limited | Real estate | 2023 |
| Harris Strategic Land (Melton) Ltd | Real estate | 2014 |
| Harris Strategic Land (New Homes) Limited | Real estate | 2019 |
| Harris Strategic Land (Rendlesham) Ltd | Real estate | 2016 |
| Harris Strategic Land (Tyneside) Ltd | Real estate | 2023 |
| Harris Strategic Land Ltd | Real estate | 2018 |
| Harrison & Wildon Developments Limited | Real estate | 2004 |
| Harrison & Wildon Holdings Ltd | Financial services | 2021 |
| Harrison & Wildon Limited | Construction | 1977 |
| Harrison Beaumont Insurance Services Limited | Financial services | 2002 |
| Harrows Jewellery Ltd | Wholesale & retail | 1998 |
| Harry A.Coff,Limited | Real estate | 1937 |
| Harry King & Sons Limited | Construction | 2005 |
| Hart and Smith Sports Limited | Arts & recreation | 2023 |
| Hart Eggs Limited | Wholesale & retail | 2004 |
| Hart&Mickelsen Brickwork Ltd | Construction | 2021 |
| Hartley and Curran Ltd | Construction | 2016 |
| Hartley Estates Limited | Real estate | 2019 |
| Hartpalm Limited | Manufacturing | 2021 |
| Harts Carpets & Flooring Ltd | Wholesale & retail | 2025 |
| Hartsmorr Properties Limited | Real estate | 2022 |
| Hartwood Floors Limited | Wholesale & retail | 2011 |
| Harty J Wells Engineering Limited | Professional & scientific | 2023 |
| Harvey Armstrong Properties Ltd | Real estate | 2022 |
| Harvey Rose Estates Ltd | Real estate | 2021 |
| Harvia Limited | Professional & scientific | 2015 |
| Harward Year Manufacturing Limited | Manufacturing | 2025 |
| Harwich Fast Food Ltd | Hospitality | 2025 |
| Harwich Port Users' Association Limited | Other services | 1985 |
| Harwich Village Lettings Ltd | Real estate | 2023 |
| Haselton Construction Ltd | Construction | 2020 |
| Haselton Property Ltd | Real estate | 2023 |
| Hashtag and Co Trading Limited | Wholesale & retail | 2024 |
| Hask Homes Ltd | Construction | 2019 |
| Haslechurch Limited | Extraterritorial | 2016 |
| Haslemere Farm (Traditional Breeds) Limited | Agriculture & fishing | 2004 |
| Hasler Hawkins Engineering Services Limited | Construction | 1978 |
| Hasuvara Solutions Ltd | Wholesale & retail | 2025 |
| Hatfield Road and Santiago Way RTM Company Limited | Administrative & support | 2011 |
| Hatmer Limited | Hospitality | 2026 |
| Hattons Haulage Ltd | Transport & logistics | 2025 |
| Haulage Ltd | Transport & logistics | 2019 |
| Haulfix Ltd | Wholesale & retail | 2025 |
| Haus Capital Group Ltd | Financial services | 2025 |
| Haus Offsite Ltd | Financial services | 2023 |
| Haus Property Development Ltd | Construction | 2025 |
| Haus Tech Ltd | Information & communication | 2023 |
| Haute Performance Limited | Administrative & support | 2023 |
| Haven Homes Properties Limited | Real estate | 2025 |
| Haven Refrigeration Ltd | Manufacturing | 2013 |
| Haverhill Chamber of Commerce Ltd. | Other services | 2014 |
| Haverhill Property Management Limited | Construction | 1988 |
| Havilah Pishon International Ltd. | Administrative & support | 2025 |
| Haward Horological Limited | Manufacturing | 1975 |
| Haway Limited | Professional & scientific | 2016 |
| Hawk Express Cabs Limited | Transport & logistics | 1991 |
| Hawk Express Limited | Transport & logistics | 1998 |
| Hawk Trans I.N. Ltd | Transport & logistics | 2025 |
| Hawker Aeronautical Engineering Ltd | Professional & scientific | 2021 |
| Hawker Restorations Limited | Manufacturing | 1993 |
| Hawkins Brickwork Services Ltd | Construction | 2022 |
| Hawkins Homecare Limited | Administrative & support | 2002 |
| Hawkley Properties Ltd | Real estate | 2018 |
| Hawks Mill Associates Limited | Households | 1997 |
| Hawksmoor Residential Limited | Real estate | 2019 |
| Haxley & Ruffles Limited | Construction | 2013 |
| Hayat Place Ltd | Wholesale & retail | 2020 |
| Haydn Evans Consulting Limited | Professional & scientific | 2000 |
| Haydn Evans Consulting Trustee Limited | Financial services | 2023 |
| Haydn Jacks Limited | Real estate | 2013 |
| Haydonning Limited | Arts & recreation | 1979 |
| Hayes Court Freehold Company Limited | Real estate | 2008 |
| Hayes Homes Southern Limited | Real estate | 2019 |
| Hayley Sparkes Ltd | Professional & scientific | 2010 |
| Haytrax Ltd | Manufacturing | 2015 |
| Hayward Moon Limited | Other services | 2007 |
| Hazel Grove (Watton) Management Company Limited | Households | 2018 |
| HB Bookkeeping Ltd | Administrative & support | 2017 |
| HBC Carpentry Ltd | Manufacturing | 2025 |
| Hbcps Trustee Limited | Financial services | 2024 |
| Hbhs Enterprise Ltd | Wholesale & retail | 2023 |
| HBL Social Care Limited | Health & social care | 2025 |
| HC Legionella Ltd | Professional & scientific | 2023 |
| HC Technical Consulting and Contracting Services Limited | Professional & scientific | 2014 |
| HD Car Care Ltd | Wholesale & retail | 2025 |
| HD Roofing Contractors Ltd | Construction | 2026 |
| Hdcr Ltd | Other services | 2019 |
| Hdmc Foods Ltd | Hospitality | 2025 |
| Headnest Ltd | Manufacturing | 2025 |
| Headset Consulting Limited | Professional & scientific | 2025 |
| Headway Suffolk and Norfolk Ltd | Health & social care | 1999 |
| Healey Dell Developments Ltd | Construction | 2020 |
| Healeys Printers Limited | Manufacturing | 1997 |
| Healing Minds and Community Recovery CIC | Administrative & support | 2025 |
| Health Counts Aesthetic and Skin Laser Clinic Limited | Health & social care | 2018 |
| Health First Wellness Limited | Health & social care | 2025 |
| Health Initiatives Limited | Administrative & support | 2005 |
| Health&Homecare Ltd | Health & social care | 2026 |
| Health-Ai Holdings Limited | Health & social care | 2020 |
| Healthcare Connext Ltd | Health & social care | 2023 |