| Haley Vehicle Movements Ltd | Wholesale & retail | 2012 |
| Halfpenny Mews Management Company Ltd | Extraterritorial | 2005 |
| Halftown Limited | Construction | 2013 |
| Halib Foods Limited | Extraterritorial | 2003 |
| Haller Gesine Limited | Wholesale & retail | 2024 |
| Hallerclarke Limited | Professional & scientific | 2022 |
| Halliday Homes Ltd | Wholesale & retail | 2025 |
| Halliday Lowry Limited | Professional & scientific | 2004 |
| Hallmark Solutions Limited | Information & communication | 1990 |
| Hallmount Properties Ltd | Other services | 2018 |
| Hallowed Heart Ltd | Other services | 2024 |
| Halo (Belfast) Realisations Limited | Professional & scientific | 2019 |
| Halo Hair Toppers Ltd | Other services | 2025 |
| Halo Private Enterprise Ltd | Construction | 2025 |
| Halo Technologies Europe Limited | Administrative & support | 2019 |
| Halo Technologies Limited | Information & communication | 2025 |
| Halonor Trading Co Ltd | Wholesale & retail | 2022 |
| Hambro Northern Ireland Ventures LP | | 1995 |
| Hamel Homes Ltd | Real estate | 2018 |
| Hamel Mews Management Company Limited | Professional & scientific | 2015 |
| Hamid & Sons Belfast Limited | Real estate | 2024 |
| Hamill Bosket Limited | Professional & scientific | 2015 |
| Hamilton & Kirk Limited | Hospitality | 1967 |
| Hamilton Agencies Ltd | Wholesale & retail | 2001 |
| Hamilton Architects LLP | | 2011 |
| Hamilton Bona Ltd | Wholesale & retail | 2022 |
| Hamilton Developments (NI) Ltd | Construction | 2007 |
| Hamilton Face Clinic Ltd | Health & social care | 2017 |
| Hamilton Flooring Ltd | Construction | 2016 |
| Hamilton Shipping (Port Services) Limited | Transport & logistics | 2000 |
| Hamilton Shops Ltd | Hospitality | 2023 |
| Hamilton Software Design Ltd | Information & communication | 2019 |
| Hamilton Terrace Ltd | Households | 2003 |
| Hamiltonr Limited | Wholesale & retail | 2025 |
| Hamlet Orchardvale Management Company Limited | Households | 2015 |
| Hammerfort Alliance LP | | 2017 |
| Hammerstone House Limited | Information & communication | 2013 |
| Hammond Metal Recycling Limited | | 2000 |
| Hampden Group Limited | Wholesale & retail | 1976 |
| Hampton Court Owners Management Company Limited | Households | 2002 |
| Hampton Estate Agency Limited | Real estate | 2005 |
| Hampton Homes (N.I.) Ltd | Real estate | 2000 |
| Hampton Mews Management Limited | Extraterritorial | 2008 |
| Hampton Park Finance Limited | Financial services | 2023 |
| Hampton Properties (N.I.) Ltd | Real estate | 2020 |
| Hamzaeon Limited | Wholesale & retail | 2024 |
| HAN Solar Ltd | Construction | 2025 |
| Hana Women’S Health Ltd | Health & social care | 2025 |
| Hand Boiler Maintenance Ltd | Manufacturing | 2014 |
| Handing Rose Trading Ltd | Wholesale & retail | 2025 |
| Hands on Beauty Ltd | Other services | 2022 |
| Handsom Ltd | Professional & scientific | 2025 |
| Hanella Ltd | Professional & scientific | 2023 |
| Hanfield Logistics LP | | 2017 |
| Hanjin Trade Limited | Manufacturing | 2023 |
| Hanlea Property Developments Limited | Construction | 2025 |
| Hanley Morton (Life, Pensions & Investments) Limited | Financial services | 1987 |
| Hanna Mechanical Ltd | Construction | 2025 |
| Hanna Mechanical Services (Ni)Llp | | 2007 |
| Hanna Thompson Limited | Extraterritorial | 2017 |
| Hannah Christie Ltd | Professional & scientific | 2026 |
| Hannah Mckimm Ltd | Professional & scientific | 2026 |
| Hannahstown Tyre & Auto Centre Ltd | Wholesale & retail | 2011 |
| Hannan Landed Property Ltd | Real estate | 2023 |
| Hannigans Developments Limited | Real estate | 2024 |
| Hannon Travel NI Limited | Administrative & support | 2018 |
| Hanrose Limited | Real estate | 2020 |
| Hanwood Filling Station Ltd | Wholesale & retail | 2014 |
| Hanwood Trust Company Limited | Arts & recreation | 2002 |
| Hanxuefei Ltd | Wholesale & retail | 2025 |
| Hapa Properties Limited | Real estate | 2021 |
| Happenstance Labs Ltd | Information & communication | 2026 |
| Happily FLY Ltd | Wholesale & retail | 2024 |
| Happy Bubbles Laundry Service Ltd | Other services | 2026 |
| Happy Counts Limited | Wholesale & retail | 2026 |
| Happy Days Arts Community Interest Company | Arts & recreation | 2025 |
| Happy Days: Eibf Limited | Arts & recreation | 2012 |
| Happy Haven Group Ltd | Health & social care | 2023 |
| Happy Hospitality Ltd | Hospitality | 2025 |
| Happy House DA HAI Limited | Hospitality | 2020 |
| Happy Life Together NI CIC | Agriculture & fishing | 2023 |
| Happy on the Inside Design Ltd | Extraterritorial | 2023 |
| Happy OUT Cafe Limited | Hospitality | 2023 |
| Happy OUT Coffee Ltd | Hospitality | 2022 |
| Happy OUT Limited | Hospitality | 2023 |
| Happy Shiba Ltd | Hospitality | 2020 |
| Happy the Hoglet Limited | Information & communication | 2018 |
| Happy Women of Belfast Limited | Education | 2025 |
| Happy Yemen Ltd | Hospitality | 2025 |
| Happydog Restaurants Limited | Hospitality | 2017 |
| Happyfest Ltd | Administrative & support | 2023 |
| Happyireland Productions Ltd | Manufacturing | 2013 |
| Hapsoft Consulting Ltd | Information & communication | 2015 |
| Hapspring Limited | Wholesale & retail | 2023 |
| Harahood Clothing Ltd | Wholesale & retail | 2023 |
| Harambee Limited | Wholesale & retail | 2013 |
| Harberry First AID Training Limited | Education | 2020 |
| Harberthorn Holdings Ireland Limited | Real estate | 2026 |
| Harberton Estate Management Company Limited | Households | 2015 |
| Harberton Specialist Engineering Solutions Limited | Manufacturing | 2022 |