| Hogs Inn the Venue Ltd | Arts & recreation | 2026 |
| Hogs Inn Victoria Vaults Ltd | Hospitality | 2025 |
| Homefix Plumbing and Heating Limited | Construction | 2024 |
| Horne and Meredith Properties Limited | Real estate | 1997 |
| Horologium Precision Ltd | Other services | 2019 |
| Hotel Partner Solutions Limited | Professional & scientific | 2023 |
| Hoverhawk Ltd | Agriculture & fishing | 2024 |
| Howells Trading Limited | Professional & scientific | 2024 |
| Hygieia EIR Limited | Health & social care | 2020 |
| I C Shipping Limited | Transport & logistics | 2004 |
| I T Jerman Ltd | Manufacturing | 2020 |
| IAN Ellis Limited | Professional & scientific | 2004 |
| ID Burley Limited | Professional & scientific | 2006 |
| IH Building Services Limited | Construction | 2011 |
| Images (Welshpool) Limited | Hospitality | 1998 |
| Imso Ltd | Professional & scientific | 1999 |
| Infoquest Enterprises Ltd | Information & communication | 2025 |
| Ingested Ltd | Information & communication | 2021 |
| Inncat Ltd | Professional & scientific | 2022 |
| Interior Products Group Limited | Manufacturing | 1967 |
| Irehab Ltd | Wholesale & retail | 2019 |
| Isallt Consulting Limited | Information & communication | 2014 |
| Isca Mercatura Limited | Information & communication | 2003 |
| Islands Management Limited | Administrative & support | 2009 |
| ISR Enterprise Limited | Wholesale & retail | 2023 |
| Itcom Tech Solutions Ltd | Information & communication | 2025 |
| Ithon Valley Ltd | Hospitality | 2023 |
| Ivansp Ltd | Transport & logistics | 2022 |
| J & M Whittingham Ltd | Wholesale & retail | 2007 |
| J a Baker and SON Limited | Construction | 2003 |
| J a Smith Limited | Professional & scientific | 2010 |
| J Plumbing & Building Ltd | Construction | 2020 |
| J Trimble Legal Services Limited | Professional & scientific | 2018 |
| J. a. Bowen & Co. Contracting Limited | Construction | 2002 |
| Jacks Tyres Limited | Wholesale & retail | 2010 |
| Jacktrans Limited | Transport & logistics | 2010 |
| JAL Management LLP | | 2008 |
| James & Jean Potter SW1 Ltd | Real estate | 2022 |
| James and Jean Potter Limited | Agriculture & fishing | 2019 |
| James Penybank Ltd | Agriculture & fishing | 2026 |
| JC Tree and Garden Care Ltd. | Agriculture & fishing | 2024 |
| Jenkins Housing Limited | Real estate | 2018 |
| Jenners Online Ltd | Wholesale & retail | 2024 |
| Jepbox Limited | Financial services | 2025 |
| Jeremy RYE Limited | Wholesale & retail | 2010 |
| JIM Blurton Farrier Tools Limited | Wholesale & retail | 1995 |
| JIM Blurton Specialist Horseshoes Limited | Manufacturing | 2006 |
| John Lowe Electrical Ltd | Construction | 2005 |
| John Morris Holdings Limited | Professional & scientific | 2009 |
| Jonathan LEE Holdings Limited | Financial services | 2025 |
| Jonathan LEE Investments Limited | Real estate | 2025 |
| Jonathan Partridge Optometrists Limited | Wholesale & retail | 2003 |
| Joseli Ltd | Professional & scientific | 2022 |
| Joshua PEG Ltd | Professional & scientific | 2022 |
| K & C Yarwood Limited | Manufacturing | 1999 |
| KA Agri Ltd | Agriculture & fishing | 2014 |
| Kairos Leadership Development Ltd | Professional & scientific | 2010 |
| Kalahari Events Ltd | Administrative & support | 2018 |
| KBARBERS1 Ltd | Other services | 2025 |
| KC People Management Solutions Ltd | Administrative & support | 2022 |
| KEN Law Safety Limited | Professional & scientific | 2012 |
| Kenand Housing Limited | Real estate | 2013 |
| Kenton Jones Limited | Manufacturing | 2001 |
| KFM Mold Limited | Wholesale & retail | 2011 |
| King Victorian Ltd | Real estate | 2025 |
| Kings Nurseries Limited | Wholesale & retail | 2020 |
| Kingswood Arms (Forden) Ltd | Hospitality | 2026 |
| Kingswood Church | Other services | 2008 |
| Kingswood Frames and Mirrors/Framework Studio Limited | Manufacturing | 2001 |
| Kipper Club Ltd | Manufacturing | 2023 |
| Kolmag Ltd | Wholesale & retail | 2023 |
| Kralex Ltd | Transport & logistics | 2024 |
| Kriger Boilers UK Limited | Manufacturing | 2019 |
| Kynaston Poultry Limited | Agriculture & fishing | 2009 |
| L F Fence and Farm Limited | Wholesale & retail | 2026 |
| LA Clusaz Limited | Financial services | 2023 |
| Lake Vyrnwy Animals and Crafts Ltd | Arts & recreation | 2023 |
| Lawrence Menhinick Ltd | Information & communication | 1989 |
| Leema Electro Acoustics Limited | Manufacturing | 2014 |
| Leeson Fabrication Limited | Manufacturing | 2026 |
| Leighton Farms Limited | Agriculture & fishing | 2024 |
| LES Owen Dairy Supplies Limited | Agriculture & fishing | 2002 |
| Lewis M Consultancy Ltd | Professional & scientific | 2022 |
| Lion Hotel (Berriew) Limited | Real estate | 2018 |
| Little Acorns Children’S Daycare Ltd | Education | 2020 |
| Little Lion Dragon Studio Ltd | Information & communication | 2026 |
| Living Comfortably Ltd | Real estate | 2019 |
| LJE Estates Limited | Real estate | 2021 |
| Llanerchydol Hall Limited | Hospitality | 2023 |
| Llugwy Investments Limited | Real estate | 2023 |
| Llwyn Developments Limited | Construction | 1997 |
| Llwyn Estates Limited | Construction | 1997 |
| Loadcontrol Limited | Professional & scientific | 1988 |
| Loki Services Limited | Construction | 2004 |
| Long Mountain View Management Company Limited | Households | 2024 |
| Long Tall Diva Ltd | Arts & recreation | 2012 |
| Lowfield Timber Frames Limited | Manufacturing | 2006 |
| LP Ingram Limited | Professional & scientific | 2010 |
| Lunchlocker Systems Limited | Administrative & support | 2021 |
| Luvata Welshpool Limited | Manufacturing | 2015 |