| Indyhealth Limited | Health & social care | 2021 |
| Information Rules OK Ltd | Information & communication | 2011 |
| Inna Wellness Ltd | Health & social care | 2019 |
| International Contractor Support Ltd | Professional & scientific | 2018 |
| Internet Product Centre Limited | Information & communication | 2022 |
| ION Sky Ltd | Professional & scientific | 2023 |
| Ironclad Logistics Ltd | Transport & logistics | 2025 |
| Isbei Limited | Professional & scientific | 2019 |
| Isco Metalwork Limited | Manufacturing | 2020 |
| Island Crest Limited | Information & communication | 2017 |
| J C Scenery Construction Limited | Manufacturing | 2018 |
| Jabba Cleaning Services Limited | Administrative & support | 2025 |
| Jack Fertility Ltd | Wholesale & retail | 2022 |
| James Ashley Limited | Information & communication | 2024 |
| James Family Investments Ltd | Financial services | 2024 |
| Jampac Limited | Real estate | 2015 |
| JBL Management Limited | Real estate | 2013 |
| JCA Edits Ltd | Information & communication | 2016 |
| Jerry Bull Consulting Ltd | Professional & scientific | 2022 |
| Jggg Financial Planning Ltd | Financial services | 2022 |
| Jkplumber Limited | Construction | 2022 |
| Jmmk Consultancy Limited | Professional & scientific | 2026 |
| JOB Construction Ltd | Professional & scientific | 2016 |
| Joco Dance and Theatre Arts LLP | | 2018 |
| Johanna FRY Films Ltd | Information & communication | 2022 |
| John and Paul Decor Ltd | Construction | 2024 |
| Jonathan Cole Photography Ltd | Professional & scientific | 2012 |
| JS West Limited | Construction | 2010 |
| JTE Jungian Analysis & Psychotherapy Ltd | Health & social care | 2026 |
| Junaid Locums Ltd | Health & social care | 2024 |
| Just Global HR Services Limited | Professional & scientific | 2019 |
| K2V2 Limited | Information & communication | 2025 |
| Kate Freedman Coaching Limited | Professional & scientific | 2017 |
| Kate Goodwin Ltd | Manufacturing | 2026 |
| Kazansky Ltd | Wholesale & retail | 2025 |
| Kench Project Consulting Ltd | Professional & scientific | 2014 |
| Keynsham Property Company Limited | Real estate | 1956 |
| Kghb Limited | Real estate | 2018 |
| Khankah Sirajia Limited | Information & communication | 2012 |
| Khankah Sirajia UK Limited | Construction | 2020 |
| Kickstart Consultancy Limited | Professional & scientific | 2025 |
| Kingfisher Domains Limited | Professional & scientific | 2011 |
| Kingfisher Drive Residents Association Limited | Households | 1973 |
| Kirkland's Kontractor's Limited | Professional & scientific | 2022 |
| KJT Property Group Ltd | Financial services | 2026 |
| Klein Limited | Professional & scientific | 1997 |
| Knach Ltd | Professional & scientific | 2011 |
| KPM Elite Ltd | Real estate | 2025 |
| KPT Building Contractors Ltd | Construction | 2020 |
| Langley Groundworks Ltd | Construction | 2025 |
| Langwood Close Residents Limited | Professional & scientific | 2004 |
| Larby Partners Limited | Extraterritorial | 2017 |
| LDB Consulting Limited | Professional & scientific | 2011 |
| Leadcreate Limited | Administrative & support | 2026 |
| Leadership Growth Consulting Limited | Administrative & support | 2026 |
| Leethgrove Investment Co.Limited | Real estate | 1964 |
| Let's AV IT Ltd | Information & communication | 2018 |
| Let's Rent Local Limited | Real estate | 2016 |
| Lifemore Limited | Wholesale & retail | 2007 |
| Limebush Holdings Limited | Financial services | 2026 |
| Links Road Management Company Limited | Households | 2010 |
| Lions Innovations Ltd | Extraterritorial | 2019 |
| Liquid Project Services Limited | Professional & scientific | 2006 |
| Liquidgoldwhiskycompany Limited | Administrative & support | 2015 |
| Lisyl Consulting Ltd | Health & social care | 2018 |
| Lisyl Properties Limited | Real estate | 2021 |
| Little Property Investment Ltd | Real estate | 2021 |
| Liverpool Street Capital Advisors Ltd | Professional & scientific | 2021 |
| Lluxl Limited | Manufacturing | 2024 |
| Lomax Brands Ltd | Information & communication | 2022 |
| Lomax Property Ltd | Real estate | 2012 |
| London Golf Limited | Administrative & support | 2005 |
| London Quintessential Ltd | Extraterritorial | 2015 |
| Longshaw Limited | Extraterritorial | 2018 |
| LOVE2DANCE Limited | Arts & recreation | 2019 |
| Lovegrove Associates Ltd | Administrative & support | 2026 |
| Lucey Hair Ltd | Other services | 2014 |
| Lunar Partners Ltd | Information & communication | 2017 |
| Lurway Renovations Ltd | Construction | 2025 |
| Lussuosa Ltd | Wholesale & retail | 2021 |
| Lysis Gaming Compliance Ltd | Administrative & support | 2020 |
| M Squared Business Support Ltd | Administrative & support | 2025 |
| M Whiteley Nutrition Ltd | Health & social care | 2021 |
| M.R.S. Brothers Limited | Real estate | 1999 |
| Mace (U.K.) Limited | Real estate | 1984 |
| Marble Hill Limited | Households | 2017 |
| March Forth Limited | Professional & scientific | 2025 |
| Marisa Writes Ltd | Professional & scientific | 2023 |
| Marjot Ltd | Professional & scientific | 2022 |
| Mark Coysh Ltd | Real estate | 2025 |
| Martin Way Properties Limited | Real estate | 1954 |
| Marvellous Merchandising Limited | Wholesale & retail | 2017 |
| Mason & Daka Ltd | Extraterritorial | 2019 |
| Mason AI Limited | Information & communication | 2024 |
| Matrix Realms Ltd | Arts & recreation | 2015 |
| Maughan & Mccay Ltd | Real estate | 2016 |
| Mauripharm (Leatherhead) Ltd | Wholesale & retail | 2013 |
| Mauripharm Properties Limited | Construction | 2025 |
| Mcgraw Media Ltd | Information & communication | 2024 |
| Mede Homes Limited | Households | 2023 |