| Grgr Enterprises Limited | Professional & scientific | 2018 |
| Grgr Property Limited | Real estate | 2020 |
| GRM Film Ltd | Administrative & support | 2025 |
| Growth PM Consulting Limited | Information & communication | 2022 |
| GS Property Solutions Ltd | Real estate | 2020 |
| GUS Commercials Limited | Wholesale & retail | 2004 |
| Gusto Business Consultancy Limited | Professional & scientific | 2012 |
| GWM Developments Limited | | 1989 |
| GYM101 Limited | Arts & recreation | 2021 |
| Gymfun (2025) Ltd | Arts & recreation | 2025 |
| H & H Tipene Property Holdings Ltd | Real estate | 2026 |
| Hacida Group Ltd | Real estate | 2023 |
| Hall Family Company (2025) Limited | Professional & scientific | 2025 |
| Hall Farms (Ballyhone) Limited | Agriculture & fishing | 2019 |
| Halliday Property Management Ltd | Real estate | 2023 |
| Hallmark Groceries Ltd | Wholesale & retail | 2025 |
| Hallmark Grocery Ltd | Wholesale & retail | 2025 |
| Hallmark Property Ltd | Real estate | 2025 |
| Hamilton Lets Ltd | Real estate | 2021 |
| Hanna Consultancy Services Limited | Health & social care | 2017 |
| Hanna Properties (NI) Ltd | Hospitality | 2012 |
| Hanna's Boom Box Ltd | Information & communication | 2026 |
| Happy Littles Play Company Ltd | Education | 2023 |
| Hard HAT Catering Belfast Ltd | Hospitality | 2022 |
| Harmony Vale Limited | Hospitality | 2021 |
| Harriette Enterprises Ltd | Real estate | 2015 |
| Harvey Group PLC | Construction | 1978 |
| Hawk Walks N.I Limited | Education | 2019 |
| Hawthorne Fine Boxes Ltd | Manufacturing | 2016 |
| Hazelwood Solutions Limited | Information & communication | 2026 |
| Hbdn (NI) Limited | Health & social care | 2017 |
| HBE Studios Ltd | Information & communication | 2024 |
| HE Consulting Ltd | Professional & scientific | 2026 |
| Hedge Honcho Ltd | Administrative & support | 2017 |
| Hefer Productions Ltd | Information & communication | 2025 |
| Height for Hire (Safety Training) Limited | Other services | 1999 |
| Helios GAS Ltd | Construction | 2021 |
| Henderson Foodservice Limited | Hospitality | 1967 |
| Henderson Group Property Limited | Real estate | 1987 |
| Henderson Technology Limited | Information & communication | 2009 |
| Henderson Wholesale Limited | Wholesale & retail | 1923 |
| Heritage Developments Northern Ireland Limited | Construction | 1996 |
| Heruso Group Ltd | Construction | 2024 |
| Heuristicks Ltd | Information & communication | 2020 |
| Hexlabs.Io Ltd | Information & communication | 2020 |
| HEY Darlin' Limited | Hospitality | 2024 |
| High Points Youth Ballet C.I.C. | Education | 2011 |
| Highfield Management (Block a) Limited | Real estate | 2008 |
| Highfield Management (Block B) Limited | Real estate | 2008 |
| Highfield Management (Block C) Limited | Real estate | 2008 |
| Hill Utilities Ltd | Administrative & support | 2016 |
| Hillier & Keating Properties Ltd | Real estate | 2023 |
| Hillside Nursery Ltd | Wholesale & retail | 2018 |
| Hillview Business Services Limited | Information & communication | 2014 |
| Hillview Mews Management Company Limited | Real estate | 2007 |
| Hillview Residential Limited | Construction | 2026 |
| Hirelogic Limited | Information & communication | 2018 |
| HJ Engineering Ltd | Professional & scientific | 2025 |
| Hjhp Ltd | Real estate | 2025 |
| Hmbs (N.I.) Limited | Construction | 2016 |
| HMK Car Sales Ltd | Wholesale & retail | 2021 |
| Hodge's Butchers Ltd | Wholesale & retail | 2018 |
| Honar Technology Limited | Information & communication | 2025 |
| HOP 2 Vine Limited | Wholesale & retail | 2023 |
| Horan Cardiology Limited | Health & social care | 2025 |
| Horizon Property Maintenance Ltd | Construction | 2020 |
| Horizon Trailers UK Limited | Manufacturing | 2024 |
| House of Hamon Limited | | 1987 |
| Houston Thornton & Co Limited | Construction | 2010 |
| Houtman Scaffolding Limited | Construction | 2015 |
| HQ Barbers Ltd | Other services | 2026 |
| HR Jess Ltd | Construction | 2006 |
| HS Techno Ltd | Information & communication | 2023 |
| HSJ MED LEG Services Ltd | Administrative & support | 2026 |
| Hughes Leisureland Ltd | Hospitality | 2010 |
| Hull Home Solutions Limited | Real estate | 2025 |
| Humberston Recruitment Limited | Administrative & support | 2025 |
| Humongo Limited | Information & communication | 2018 |
| Hunter Accommodation NI Ltd | Hospitality | 2024 |
| Hy-Brasil Ltd | Manufacturing | 2025 |
| Hybrid Property Maintenance Ltd | Administrative & support | 2021 |
| Hypnohome Ltd | Health & social care | 2025 |
| I AM Nurture CIC | Education | 2025 |
| I Grow Carpet Limited | Wholesale & retail | 2024 |
| I-Sys Technical Ltd | Professional & scientific | 2014 |
| Ibrand Everything Limited | Professional & scientific | 2022 |
| Ibrowide Limited | Public administration | 2024 |
| Icleanitup Ltd | Administrative & support | 2024 |
| Idini Aviation Support Limited | Manufacturing | 2017 |
| IEI Ltd | Wholesale & retail | 2025 |
| Iess (NI) Ltd | Administrative & support | 2025 |
| Ihomes Medical LLP | | 2011 |
| Ikon Property Ltd | Real estate | 2016 |
| Impact Health Physio Ltd | Health & social care | 2024 |
| Impact Ireland (Metals N.I.) Limited | Wholesale & retail | 1996 |
| Indian EX Limited | Hospitality | 2023 |
| Indian Glengormly Limited | Hospitality | 2018 |
| Industrial Supplies (NI) Ltd | Wholesale & retail | 2008 |
| Infinitus Consulting UK Ltd | Professional & scientific | 2025 |
| Infinitus Financial Ltd | Financial services | 2026 |