| Heat Source Innovation Ltd | Construction | 2025 |
| Heath Goodhand Building Limited | Construction | 2003 |
| Heavy Goods Vehicle Drivers Limited | Transport & logistics | 2014 |
| Helen Goring Line Dance Ltd | Education | 2026 |
| Helen Maybanks Photography Limited | Other services | 2012 |
| Helix Installations Ltd | Construction | 2025 |
| Helix Power Ltd | Real estate | 2023 |
| HELIX50POWER Ltd | Construction | 2025 |
| Hemswell Biogas Limited | Energy | 2014 |
| Hemswell Clean Tech Green Power Ltd | Energy | 2020 |
| Hemswell Cliff General Store Limited | Wholesale & retail | 2016 |
| Hemswell Investments Limited | Real estate | 1986 |
| Hemswell Power Solutions Limited | Energy | 2020 |
| Henmax Zero Ltd | Transport & logistics | 2021 |
| Heritage Book Vault & Company Community Interest Company | Education | 2025 |
| Heritage Book Vault Ltd | Wholesale & retail | 2025 |
| Heron Information Management LLP | | 2013 |
| Herondale Holdings Limited | Financial services | 2018 |
| Herondale Properties Limited | Real estate | 2015 |
| Herridge Propertys Ltd | Real estate | 2022 |
| Hexadex Limited | Professional & scientific | 1991 |
| Heynings Solis Limited | Agriculture & fishing | 2024 |
| HFS Cleaning Ltd | Administrative & support | 2022 |
| Hibiscus Renovations Ltd | Construction | 2017 |
| High Voltage Discos Limited | Arts & recreation | 2024 |
| Higher Skills Training Ltd | Education | 2021 |
| Highfields Limited | Health & social care | 2009 |
| Highways Heroes Awards Ltd | Construction | 2021 |
| Hillcrest Early Years Academy Limited | Education | 2012 |
| HJ Cladding Services Ltd | Construction | 2018 |
| HJ Free House Ltd | Hospitality | 2024 |
| HK Timbers Limited | Manufacturing | 2002 |
| HLH Optical Limited | Health & social care | 2023 |
| HLM Housekeeping Ltd | Administrative & support | 2022 |
| HLR Hospitality Limited | Hospitality | 2023 |
| Hodgkinson Lawrence Ltd | Real estate | 2019 |
| Hollywood Nails 108 Gainsborough Ltd | Other services | 2025 |
| Holme Bioenergy Limited | Energy | 2018 |
| Holridge Transport Limited | Transport & logistics | 2011 |
| Home Bird Property Services Ltd | Real estate | 2022 |
| Home SOS Network Ltd | Manufacturing | 2016 |
| Honeybee Childcare (Lincs) Ltd | Health & social care | 2025 |
| Hooton Engineering Limited | Extraterritorial | 2021 |
| Hooves & Whiskers Ltd | Agriculture & fishing | 2024 |
| Horgains Holdings Ltd | Financial services | 2026 |
| Hotchin Builders Limited | Construction | 2009 |
| Hotvine Ltd | Information & communication | 2020 |
| Hourglass Sport Promotions Limited | Arts & recreation | 2020 |
| House of B Limited | Other services | 2023 |
| House of Choy Cantonese Ltd | Hospitality | 2022 |
| HR IS for ALL Ltd | Professional & scientific | 2025 |
| HRH Property Investments Ltd | Real estate | 2025 |
| HRS Hospitality Recruitment Limited | Administrative & support | 2025 |
| HRS Hospitality Recruitment Solutions Limited | Administrative & support | 2025 |
| Hubble Architecture Limited | Professional & scientific | 2022 |
| Humber Power Engineering Services Limited | Professional & scientific | 2006 |
| Hume London Limited | Manufacturing | 2024 |
| Hunter Technical Services Limited | Manufacturing | 2023 |
| Huntsman Homes Ltd | Construction | 2017 |
| Hurst Inno-Tech Limited | Administrative & support | 2023 |
| Hxll Ecommerce Limited | Wholesale & retail | 2019 |
| Hydrink Limited | Wholesale & retail | 2022 |
| Hyhtan Limited | Information & communication | 2013 |
| I & H Cleary Properties Ltd | Real estate | 2025 |
| I MM International & UK Haulage Ltd | Transport & logistics | 2025 |
| I-Keg Limited | Manufacturing | 2019 |
| I.G. Watson Plant Ltd | Construction | 2017 |
| IBUDDY247 Ltd | Information & communication | 2023 |
| Ibuild Developments Limited | Construction | 2020 |
| Icare Forensic Limited | Health & social care | 2012 |
| ICC Business Solutions Limited | Professional & scientific | 2011 |
| Identity Access Management Consultancy Ltd | Information & communication | 2019 |
| Ignited Brands Ltd | Wholesale & retail | 2025 |
| IL Gusto Italia Ltd | Hospitality | 2024 |
| Imperial Packaging Limited | Other services | 1995 |
| Incitus Building Supplies Ltd | Administrative & support | 2025 |
| Incitus Consultants Ltd | Administrative & support | 2024 |
| Independent Software Solutions Limited | Information & communication | 2008 |
| Induction Furnace Services Limited | Manufacturing | 2015 |
| Industrial Electrical Supplies (Lincolnshire) Ltd | Wholesale & retail | 1996 |
| Industrial Rescue Ltd | Professional & scientific | 2016 |
| Ingham Aviation Heritage Ltd | Arts & recreation | 2011 |
| Innovatus International Ltd | Wholesale & retail | 2020 |
| INO Software Solutions Ltd | Information & communication | 2026 |
| Inrange Cars Ltd | Wholesale & retail | 2014 |
| Inside Interiors Solutions Ltd | Real estate | 2024 |
| Integrated Completion Solutions International Ltd | Manufacturing | 2013 |
| International Broadcast Consultancy Ltd | Professional & scientific | 2016 |
| Into Estate Agent Limited | Real estate | 2023 |
| ION Glow Limited | Information & communication | 2008 |
| Ironwater Group Ltd | Agriculture & fishing | 2026 |
| Isla Bonita Hair Ltd | Other services | 2021 |
| Istanbul Kadir Kuafor Ltd | Other services | 2021 |
| IT Soft Ltd | Other services | 2011 |
| IVY House Power Solutions Ltd | Professional & scientific | 2024 |
| J & E Importers & Distributors Green JEM MFG Associates Co Ltd | Wholesale & retail | 1992 |
| J & K Property Rentals Ltd | Real estate | 2026 |
| J & L Structural Installations Ltd | Construction | 2022 |
| J & S Packaging Limited | Manufacturing | 1996 |
| J B Joinery Services (Lincs.) Ltd | Construction | 2015 |