| H&T Solutions Ltd | Professional & scientific | 2018 |
| H.M. Venn & Sons Limited | Agriculture & fishing | 1983 |
| H3 Construction Ltd | Construction | 2022 |
| Haborn Products Limited | Manufacturing | 2022 |
| Haceby Developments Limited | Real estate | 2015 |
| Haceby Solutions Limited | Hospitality | 2019 |
| Hadgraft Case Management Limited | Health & social care | 2016 |
| Hale Engineering Limited | Manufacturing | 2023 |
| Hall Electrical Solutions Ltd | Construction | 2022 |
| Hamilton Black Property Holdings Ltd | Hospitality | 2025 |
| Hammerino Consulting Ltd | Financial services | 2024 |
| Hampshire Vascular Access Ltd | Health & social care | 2016 |
| Hanbeck (Drystone) Limited | Mining & quarrying | 2021 |
| Handley Property Ltd | Real estate | 2020 |
| Handley Street 1958 Limited | Extraterritorial | 2014 |
| Hanz Free Ltd | Professional & scientific | 2020 |
| Happy Haberdashery and Crafts Ltd | Arts & recreation | 2021 |
| Hardy Construction & Groundworks Limited | Construction | 2021 |
| Hare and Beauty Ltd | Other services | 2018 |
| Harmful Harmless Limited | Professional & scientific | 2021 |
| Harrada Limited | Real estate | 2017 |
| Harrington Equine Ltd | Wholesale & retail | 2018 |
| Harrison Bannerton Limited | Professional & scientific | 2021 |
| Hartley Appliances Ltd | Wholesale & retail | 2025 |
| Hass Barbers Ltd | Other services | 2023 |
| Haverholme Estate Limited | Arts & recreation | 2021 |
| Hazzards Emporium Ltd | Arts & recreation | 2026 |
| HC Building & Brickwork Contractors Ltd | Construction | 2024 |
| HCS (Cladding & Construction) Ltd | Construction | 2007 |
| HDB Music & Media Ltd | Information & communication | 2025 |
| Healdi Marketing & Distribution Limited | Professional & scientific | 2009 |
| Heatherose Limited | Manufacturing | 1969 |
| Heckington Windmill Trust | Arts & recreation | 2010 |
| Hedgehog Joinery Co Ltd | Manufacturing | 2026 |
| Helkinsoft Limited | Information & communication | 2005 |
| Helpringham Transport Services Limited | Wholesale & retail | 1991 |
| Hetty's Catering Ltd | Hospitality | 2025 |
| HGB Building Services Ltd | Construction | 2024 |
| HI Management Services Ltd | Real estate | 2026 |
| HI Singh Construction Ltd | Construction | 2022 |
| High Level Security Associates Limited | Information & communication | 2005 |
| High Tide Gundogs Ltd | Agriculture & fishing | 2020 |
| Highgate Meadow Ltd | Construction | 2024 |
| Highgate Meadow Management Company Limited | Households | 2026 |
| Hill Bros. (Sleaford) Limited | Wholesale & retail | 2016 |
| Hilliards Home Improvements Ltd | Construction | 2026 |
| Hilliards Tax and Accounting Ltd | Professional & scientific | 2026 |
| Hinton Civils and Surfacing Ltd | Construction | 2021 |
| Hipster Classic Autos Ltd | Wholesale & retail | 2021 |
| Hipster Motorcycles Ltd | Wholesale & retail | 2018 |
| Hirst Architecture Limited | Professional & scientific | 2023 |
| Hirst Conservation Limited | Construction | 2015 |
| Hirst Heritage Limited | Construction | 2022 |
| HJB Property and Letting Ltd | Real estate | 2022 |
| Hodgson Estates Limited | Real estate | 2015 |
| Hoggle Holdings Ltd | Real estate | 2025 |
| Holborn Wellness Rooms Ltd | Real estate | 2025 |
| Holly's Homes Ltd | Real estate | 2025 |
| Hollywood Nails KN Ltd | Other services | 2026 |
| Holme House Ltd | Real estate | 2024 |
| Holte Properties Ltd | Real estate | 2019 |
| Holton Sleaford Independent School Ltd | Education | 2020 |
| Home Designers Limited | Manufacturing | 2012 |
| Homestead Fields Maintenance Ltd | Households | 2021 |
| Honeybadger Protect Ltd | Administrative & support | 2026 |
| Hoot's Taxis Ltd | Transport & logistics | 2022 |
| Hopkins Brickwork Ltd | Construction | 2016 |
| Horne & Sidney Flooring Ltd | Wholesale & retail | 2024 |
| Horton Bros Ltd | Real estate | 2023 |
| Howseman Agriculture Limited | Agriculture & fishing | 2012 |
| Howseman Agrisupplies Limited | Wholesale & retail | 2014 |
| HPC Design & Build Ltd | Construction | 2008 |
| Hugh Mcmillen Property Ltd | Extraterritorial | 2023 |
| Hugojob Ltd | Transport & logistics | 2025 |
| Humberstone Property Ltd | Real estate | 2025 |
| Hutson Farming Company Limited | Agriculture & fishing | 2001 |
| Hydreau Ltd | Water & waste | 2017 |
| Hyperlincs Limited | Information & communication | 2016 |
| I B Electrical (Lincs) Ltd | Construction | 2020 |
| I&M Aviation Ltd | Manufacturing | 2022 |
| I.T.M. Housekeeping Services Ltd | Administrative & support | 2019 |
| IAN Baumber Tarpaulins Limited | Manufacturing | 2011 |
| IAN Dolby Business Services Ltd | Professional & scientific | 2011 |
| IAN Maxwell Barber Ltd | Construction | 2015 |
| ICARE1 Limited | Other services | 2018 |
| Icomply Consulting Limited | Professional & scientific | 2023 |
| Ideal Property Improvements Limited | Construction | 2025 |
| Ifab (Newark) Ltd | Manufacturing | 2020 |
| IMR Mechanical Ltd | Construction | 2012 |
| IN House Electrics Ltd | Construction | 2013 |
| Inbalance Labs Ltd | Other services | 2025 |
| Incloud Ites Ltd | Information & communication | 2015 |
| Inclusive Mindset Ltd | Professional & scientific | 2022 |
| Independent Communication Solutions Ltd. | Construction | 1997 |
| Indi Marketplace Limited | Real estate | 2021 |
| Indian Delights Fish and Meat Ltd | Wholesale & retail | 2024 |
| INDIGO:19 Limited | Education | 2020 |
| Inertive Ltd | Professional & scientific | 2025 |
| Infinitas Recruitment Ltd | Administrative & support | 2017 |
| Ingenium Projects Limited | Professional & scientific | 2011 |