| Integrity Worldwide LP | | 2007 |
| Intellectium Limited | Health & social care | 2020 |
| Intelligent Controls (UK) Limited | Construction | 2003 |
| Interior Projects (Southern) Limited | Construction | 1990 |
| Into the Woods Events Limited | Other services | 2026 |
| Intropath Consulting Ltd | Information & communication | 2026 |
| Invisitech AV Limited | Professional & scientific | 2009 |
| Ironbridge Scenic River Cruisers Ltd | Real estate | 1999 |
| ISA Invest Future Ltd | Real estate | 2024 |
| Isla Technical Solutions Limited | Manufacturing | 2018 |
| Islington Finance Limited | Professional & scientific | 2016 |
| Itac Investments Limited | Real estate | 2002 |
| Item-Studio Limited | Information & communication | 2006 |
| Itrackmed Limited | Professional & scientific | 2025 |
| Itrackppe Limited | Information & communication | 2020 |
| Ivypop Limited | Wholesale & retail | 2022 |
| J & K Dass Consultancy Ltd | Information & communication | 2016 |
| J & O Projects Ltd | Real estate | 2023 |
| J Hack Ltd | Information & communication | 2014 |
| J Hart Roofing Limited | Construction | 2026 |
| J P GAS and Heating Ltd | Construction | 2017 |
| J R Sound Limited | Information & communication | 2003 |
| J&H Thunder Limited | Wholesale & retail | 2023 |
| J&M Bargains Limited | Wholesale & retail | 2017 |
| J.A. Excavations Limited | Construction | 2022 |
| Jadin Properties Ltd | Real estate | 2023 |
| JAM Property Management Group Limited | Real estate | 2025 |
| JAM Travel Limited | Administrative & support | 2018 |
| James Talent Limited | Administrative & support | 2024 |
| Jancap Limited | Professional & scientific | 2012 |
| Jarrett & LAM Limited | Information & communication | 2007 |
| Jaxon PRM Consulting Ltd | Administrative & support | 2025 |
| JAY Brand PVT. Ltd | Wholesale & retail | 2007 |
| Jb's Cleaning Services Limited | Administrative & support | 2018 |
| Jb's Garden Services Limited | Administrative & support | 2006 |
| Jb’S Garden & Cleaning Services Limited | Administrative & support | 2019 |
| Jddd Limited | Real estate | 2020 |
| Jedi Rehabilitation Ventures Ltd | Health & social care | 2025 |
| Jenny Nail Salon Ltd | Other services | 2016 |
| Jerrard Moore Ltd | Construction | 2015 |
| Jetstream Solutions Limited | Professional & scientific | 2024 |
| Jfef Holdings Ltd | Financial services | 2022 |
| JG Lifeskills Support Ltd | Health & social care | 2014 |
| Jigsaw Clinic Limited | Professional & scientific | 2015 |
| JJ London Properties Limited | Real estate | 2025 |
| JK Media Ltd | Information & communication | 2023 |
| JLM Bliss Properties Limited | Households | 2023 |
| JLM O&G Limited | Hospitality | 2021 |
| Jlrh Ltd | Construction | 2025 |
| JM Cooling Solutions Ltd | Construction | 2024 |
| JMJ Management Limited | Real estate | 2009 |
| JO Meredith HR Consulting Ltd | Administrative & support | 2022 |
| John a Woolston Limited | Professional & scientific | 2011 |
| John Halpern Limited | Information & communication | 2017 |
| John Jenkins Flooring Limited | Construction | 2006 |
| John Lory (Farmers) Holdings Limited | Financial services | 1994 |
| John Lory (Farmers) Limited | Agriculture & fishing | 1964 |
| Jonathan James Blake Limited | Construction | 2016 |
| Jontor Engineering Limited | Agriculture & fishing | 1976 |
| Joseph and Partners Limited | Professional & scientific | 1996 |
| Joseph Johnson Biosearch Limited | Administrative & support | 2026 |
| Joy Ventures Ltd | Information & communication | 2016 |
| Joyce Plant Hire Limited | Administrative & support | 2010 |
| JP Gossart Ltd | Information & communication | 2015 |
| JP Media Services Ltd | Information & communication | 2017 |
| Jpec Electrical Limited | Construction | 2025 |
| JR Removals Ltd | Transport & logistics | 2024 |
| JRR Group Ltd | Transport & logistics | 2020 |
| JRR Logistics Ltd | Transport & logistics | 2021 |
| JSM Property Solutions Limited | Real estate | 2022 |
| JSP Academy Ltd | Education | 2026 |
| JT Bloombridge Ltd | Professional & scientific | 2026 |
| JT Cricket Academy Ltd | Education | 2018 |
| Junior Enterprisez Limited | Real estate | 2009 |
| JWA Brickwork Ltd | Construction | 2015 |
| K & K Textile Care Ltd | Other services | 2016 |
| K & S Betchley Property Rentals Limited | Households | 2022 |
| K R Plumbing Ltd | Construction | 2021 |
| K-Ai Sparks Ltd | Information & communication | 2025 |
| K9 Greatness Ltd | Other services | 2022 |
| KAI (LO) REN Limited | Health & social care | 2021 |
| KAM General Limited | Information & communication | 2020 |
| Kanishk Global Enterprises Ltd | Manufacturing | 2025 |
| KARA25 Ltd | Other services | 2024 |
| Kask Associates Limited | Construction | 2003 |
| Kathernandez Ltd | Wholesale & retail | 2025 |
| Kdanny Limited | Health & social care | 2025 |
| Keerth Retail Ltd | Hospitality | 2020 |
| Keestone Ltd | Construction | 2013 |
| Keestone Roofing Ltd | Construction | 2021 |
| Kengai Records Ltd | Information & communication | 2024 |
| Kenya Connections Ltd | Transport & logistics | 2024 |
| Kenya Court Residents Association Limited | Households | 2000 |
| Keystone Rise Ltd | Households | 2025 |
| KF Flooring London Ltd | Construction | 2021 |
| KFS Gritting Ltd | Administrative & support | 2021 |
| Kgosi Limited | Arts & recreation | 2015 |
| KGS Eventsphere Global Ltd | Hospitality | 2026 |
| Kiddie-Safe Ltd | Education | 2020 |
| Kiko Properties Limited | Real estate | 2020 |