| Harley Haddow Bristol Limited | Professional & scientific | 2025 |
| Harley Haddow Limited | Professional & scientific | 2013 |
| Harley Haddow Manchester Limited | Professional & scientific | 2022 |
| Harley Intertrade L.P. | | 2012 |
| Harley Universal L.P. | | 2008 |
| Harlow Ventures LP | | 2013 |
| Harlowton Capital LP | | 2013 |
| Harmanco Ltd | Professional & scientific | 2024 |
| Harmattan Consulting Ltd | Transport & logistics | 2019 |
| Harmonaize CIC | Information & communication | 2026 |
| Harmony Bridge Supply Ltd | Wholesale & retail | 2025 |
| Harmony Coaching Ltd | Health & social care | 2014 |
| Harmony Premium Trading UK Limited | Wholesale & retail | 2022 |
| Harmony Projects L.P. | | 2009 |
| Harmony Self Directed Support Limited | Health & social care | 2025 |
| Harmony Support & Care Limited | Health & social care | 2025 |
| Harmony Thai Massage & Wellness Ltd | Health & social care | 2025 |
| Harmonyharbor Wellbeing Ltd | Extraterritorial | 2026 |
| Harmonyharmony Limited | Information & communication | 2024 |
| Harnica L.P. | | 2017 |
| Harolton Sales LP | | 2011 |
| Harp & Castle Ltd. | Administrative & support | 2000 |
| Harp Corporation L.P. | | 2009 |
| Harp Estates Limited | Real estate | 2017 |
| Harper Administrative Limited | Administrative & support | 2017 |
| Harper Clinical Psychology Ltd | Professional & scientific | 2011 |
| Harper Equestrian Services Limited | Administrative & support | 2025 |
| Harper Gill Property Ltd | Real estate | 2020 |
| Harper Heights Ltd | Construction | 2025 |
| Harper Investments L.P. | | 2006 |
| Harper Mcintyre Group Ltd | Manufacturing | 2025 |
| Harper Partners LP | | 2013 |
| Harper Psychology Ltd | Professional & scientific | 2024 |
| Harper's Concierge Services Limited | Real estate | 2012 |
| Harperrig Wind Ltd | Energy | 2012 |
| Harpers Marketing LP | | 2012 |
| Harper’S Kitchen (Edin) Ltd | Hospitality | 2022 |
| Harres Investment Trading (Scotland) Partnership SP | | 2022 |
| Harringford Services LP | | 2012 |
| Harrington & Associates | | 1990 |
| Harrington and BOW Limited | Other services | 2022 |
| Harrington Impex LP | | 2012 |
| Harrington Medical Ltd | Health & social care | 2020 |
| Harrington Ventures LP | | 2012 |
| Harris Miller Properties Ltd | Real estate | 2024 |
| Harris Rheumatology Services Ltd | Education | 2019 |
| Harris Sound Ltd | Information & communication | 2021 |
| Harrison Financial Services Limited | Financial services | 2007 |
| Harrison GEO Ltd | Professional & scientific | 2026 |
| Harrisonstevens Limited | Professional & scientific | 2010 |
| Harrk Properties Ltd | Real estate | 2023 |
| Harrogate Consulting LP | | 2011 |
| Harry DH Ltd | Administrative & support | 2022 |
| Harry Hughes Catering Ltd | Hospitality | 2025 |
| Harrycat Ltd | Extraterritorial | 2012 |
| Harsco Fairerways Limited Partnership | | 2009 |
| Harsco Fairestways Limited Partnership | | 2009 |
| Harsco Fairways Partnership | | 2007 |
| Harsco Higherlands Limited Partnership | | 2009 |
| Harsco Highestlands Limited Partnership | | 2009 |
| Harsco Highlands Partnership | | 2007 |
| Harsil Associates Limited | Information & communication | 2015 |
| Hart Estates (City) Limited | Construction | 2005 |
| Hart Estates (Forthquarter) Limited | Construction | 2006 |
| Hart Estates (Granton Harbour) Limited | Real estate | 2004 |
| Hart Group LP | | 2015 |
| Harte Bookkeeping Ltd | Professional & scientific | 2026 |
| Harten Alliance LP | | 2015 |
| Hartfield Applecross Limited | Hospitality | 2019 |
| Hartfield Homes (Camptoun) Limited | Construction | 2007 |
| Hartfield Homes (Livingston) Ltd. | Real estate | 1996 |
| Hartfield Homes (Musselburgh) Limited | Real estate | 2004 |
| Hartington Property Services Limited | Real estate | 2017 |
| Hartland Corporation LP | | 2014 |
| Hartlex Trade L.P. | | 2015 |
| Hartlow Nordic L.P. | | 2016 |
| Hartman Figures Limited | Professional & scientific | 2014 |
| Hartvelt Ltd | Manufacturing | 2023 |
| Hartwell L.P. | | 2008 |
| Hartwood Windfarm Limited | Energy | 2006 |
| Harun Sahin Ltd | Information & communication | 2019 |
| Harvest Alliance LP | | 2016 |
| Harvest Corporation L.P. | | 2011 |
| Harvest Finance Overseas L.P. | | 2011 |
| Harvest Industries L.P. | | 2012 |
| Harvester Alliance LP | | 2016 |
| Harvey & London Ltd | Health & social care | 2018 |
| Harvey Nutrition Ltd | Wholesale & retail | 2016 |
| Harveylaw Ltd | Other services | 2018 |
| Harward Development LP | | 2013 |
| Harwell Medical Ltd | Health & social care | 2025 |
| Harwell Science and Innovation Campus Public Sector Limited Partnership | | 2008 |
| Harwood Private Capital SLP GP LLP | | 2020 |
| Harwood Private Capital SLP II L.P. | | 2026 |
| Harwood Private Capital SLP L.P. | | 2020 |
| Haryal Holdings Ltd | Wholesale & retail | 2025 |
| Hasan Mohamed Taher and Partner Ltd | Wholesale & retail | 2024 |
| Hasdeen Holdings LP | | 2015 |
| Haseeb Store Ltd | Wholesale & retail | 2025 |
| Hash Brown Engineering Limited | Professional & scientific | 2019 |