| Greyling Ltd | Financial services | 2002 |
| Griffin Press Publishing Limited | Information & communication | 2004 |
| Guidewell Marketing Limited | Professional & scientific | 2006 |
| Gunnersbury International UK Ltd | Health & social care | 2016 |
| Gypt.Recs Ltd | Professional & scientific | 2023 |
| H L H Services Ltd | Transport & logistics | 1998 |
| H Young (Operations) Limited | Wholesale & retail | 1961 |
| H Young Holdings Public Limited Company | Wholesale & retail | 1924 |
| H&S M&E Cost Consultants Limited | Professional & scientific | 2004 |
| H. & T. Properties Limited | Real estate | 1955 |
| H. Steade & Sons Limited | Extraterritorial | 1994 |
| H. Young (Europe) Limited | Extraterritorial | 2005 |
| H.J.Skelton & Co.,Limited | Wholesale & retail | 1911 |
| Haines Residential Limited | Real estate | 2006 |
| Halian Health Ltd | Wholesale & retail | 2012 |
| Hall Close Freeholders Association Limited | Households | 1991 |
| Hamilton House Medical Limited | Health & social care | 1984 |
| Hamilton Murray & Partners Limited | Other services | 1945 |
| Hamol Limited | Professional & scientific | 1953 |
| Happyglade Ltd | Wholesale & retail | 2022 |
| Harmony Blinds (Reading) Limited | Manufacturing | 2005 |
| Harridge Financial Services Limited | Financial services | 2009 |
| Harvey Analogue Limited | Information & communication | 1999 |
| Harwood House Limited | Health & social care | 1997 |
| Hatfield Construction Limited | Extraterritorial | 1979 |
| Hawaii FIVE-0 (UK) Limited | Extraterritorial | 1976 |
| Hawaii Five-O Limited | Extraterritorial | 1957 |
| Hawkeye Medical Limited | Professional & scientific | 2007 |
| HB Accountancy Limited | Professional & scientific | 2007 |
| Health & Education South | Education | 2001 |
| Heart UK Trading Company Limited | Other services | 1998 |
| Heathlake Financial Solutions Ltd | Financial services | 2026 |
| Heathrow Guest House Limited | Hospitality | 1997 |
| Heathrow Truck Centre Limited | Wholesale & retail | 1986 |
| Heating Ventilation and Cooling Rental Ltd | Professional & scientific | 2018 |
| Hecht Pfeiffer Limited | Extraterritorial | 1985 |
| HED Group Limited | Professional & scientific | 2001 |
| HED Pro Limited | Arts & recreation | 2004 |
| HED Sport Limited | Arts & recreation | 2001 |
| HED TKD Four Limited | Arts & recreation | 2004 |
| HED TKD Limited | Arts & recreation | 2001 |
| HED TKD One Limited | Arts & recreation | 2005 |
| HED TKD Three Limited | Arts & recreation | 2004 |
| Helen Moore Associates Limited | Professional & scientific | 2001 |
| Herongate Leisure Limited | Arts & recreation | 2003 |
| HF International Marketing Limited | Wholesale & retail | 2015 |
| HGO Consultancy Limited | Professional & scientific | 2003 |
| Hi-Kleen Limited | Arts & recreation | 2001 |
| Hickies Limited | Wholesale & retail | 1985 |
| Hicks Builders (Woodley) Limited | Construction | 1979 |
| Hicks Developments Limited | Construction | 1971 |
| Hicks Holdings (Woodley) Limited | Construction | 1979 |
| Hicks Sandford Limited | Construction | 1995 |
| Highdown Avenue Management Association Limited | Other services | 2004 |
| Higoe Ltd | Information & communication | 2007 |
| Hillbrow Residents Association Limited | Households | 1982 |
| Hillcrest Property Management Limited | Households | 1998 |
| HK Telecoms Ltd | Information & communication | 2023 |
| Hodge's Travel Limited | Transport & logistics | 1996 |
| Holdstock Associates Limited | Construction | 2001 |
| Hollywood Nail (Wokingham) Ltd | Other services | 2019 |
| Home From Home Nannies Limited | Administrative & support | 2003 |
| Home Reports Ltd | Professional & scientific | 2004 |
| Homecraft Construction Limited | Wholesale & retail | 1992 |
| Honda Finance Europe PLC | Financial services | 1996 |
| Honda Motor Europe Limited | Wholesale & retail | 1965 |
| Hong Kong Berkshire Limited | Hospitality | 2017 |
| Hortlands Irrigation Ltd | Administrative & support | 2021 |
| Hostrend Limited | | 1981 |
| House Energy Limited | Professional & scientific | 2007 |
| Houseman Associates Limited | Professional & scientific | 2006 |
| Howard Lloyd & Company,Limited | Financial services | 1912 |
| Hpaws Ltd | Professional & scientific | 2000 |
| HT Properties (2019) Limited | Real estate | 2019 |
| Hulldell Limited | Wholesale & retail | 1976 |
| Humphrey-Evans Intellectual Property Services Limited | Professional & scientific | 2004 |
| Huntersgate Limited | Information & communication | 1995 |
| Huntswood Motor Company UK LLP | | 2020 |
| Hydratec Hydraulics Limited | Manufacturing | 1995 |
| Hydrotrans Technology Limited | Professional & scientific | 2005 |
| Hyperlipidaemia Education & Atherosclerosis Research Trust UK | Health & social care | 1991 |
| I Basden Plumbing & Heating Ltd | Construction | 2016 |
| I-Ache Limited | Health & social care | 2003 |
| I-Nfer Assessment Limited | Education | 2006 |
| IAN WU & Associates Ltd. | Information & communication | 1999 |
| Ibex Limited | Wholesale & retail | 1990 |
| IBS Software UK Limited | Information & communication | 2023 |
| Iconic Software Limited | Information & communication | 1984 |
| IKK Limited | Real estate | 2005 |
| Imagicam Ltd | Professional & scientific | 2007 |
| Immediate Resources Limited | Administrative & support | 1998 |
| Impact Renovations Limited | Construction | 1991 |
| Impulsive Butterfly Effect Ltd | Wholesale & retail | 2018 |
| In-Built Care Developments Limited | Wholesale & retail | 1998 |
| In-House Business Solutions Limited | Information & communication | 2004 |
| Independent Nuclear Safety Assessment Limited | Other services | 2005 |
| Industrial Consultancy Services Ltd | Professional & scientific | 1996 |
| Industrial Noise & Vibration Centre Limited | Professional & scientific | 1986 |
| Infederation Ltd | Information & communication | 2002 |
| Infinitedistance Broadcast Services Ltd | Information & communication | 2019 |