| Jaymac Consulting Ltd | Education | 2016 |
| Jays Cleaning Services Ltd | Administrative & support | 2025 |
| JB Fitness UK Solutions Ltd | Other services | 2018 |
| JB Landmark Properties Ltd | Real estate | 2024 |
| JB Ventures Ltd | Real estate | 2026 |
| JBR Care Group Limited | Financial services | 2022 |
| JC Property Soluitions Ltd | Administrative & support | 2025 |
| JCM London Consultancy Ltd | Other services | 2022 |
| Jeffreys Court (Freehold) Limited | Real estate | 2010 |
| Jeffreys Court (Management) Limited | Real estate | 1982 |
| Jenjodigital Ltd | Information & communication | 2023 |
| Jesus Encounter Ministries UK Ltd | Other services | 2024 |
| Jewellery Bonanza Boutique Ltd | Wholesale & retail | 2014 |
| JF Utilities Limited | Energy | 2025 |
| Jheeta Construction Ltd | Construction | 2021 |
| JHT Group Limited | Wholesale & retail | 2021 |
| Jigsaw Insurance Recruitment Limited | Financial services | 2009 |
| JIJ Air Conditioning Services Ltd | Construction | 2014 |
| Jikka Limited | Construction | 2022 |
| JKS Ltd Company Limited | Health & social care | 2014 |
| JKW Tech Ltd | Information & communication | 2015 |
| Jlfastfix Ltd | Construction | 2022 |
| Joaz Ltd | Real estate | 2021 |
| JOE Nelson Air Limited | Manufacturing | 2014 |
| Joe's Barber One Ltd | Other services | 2025 |
| John Forsey Limited | Wholesale & retail | 2019 |
| John Spanton Hair Design Limited | Other services | 2022 |
| Joinery 17 Ltd | Manufacturing | 2025 |
| JON Flooring Ltd | Construction | 2020 |
| Jowss Acquisitions Ltd. | Real estate | 2019 |
| JP Smart Limited | Wholesale & retail | 2023 |
| JPM (Resources) Ltd | Information & communication | 2018 |
| JS Son's Ltd | Real estate | 2022 |
| JSA Property Management Ltd | Real estate | 2026 |
| JSM Singh Limited | Real estate | 2023 |
| Judone Systems Limited | Construction | 2015 |
| Jumlad Properties Limited | Other services | 2013 |
| Junipa Homes Limited | Real estate | 2023 |
| Juppiter Limited | Administrative & support | 2013 |
| Jurassic World Reptiles Ltd | Wholesale & retail | 2019 |
| Justlit London Ltd | Wholesale & retail | 2023 |
| Juwuralo Alasooke Limited | Wholesale & retail | 2025 |
| K & P Property Holdings Limited | Real estate | 2019 |
| K Alexander Properties Ltd | Real estate | 2019 |
| K Care Recruitment Ltd | Administrative & support | 2024 |
| K Time Care Ltd | Health & social care | 2026 |
| K4KAZMI Ltd | Wholesale & retail | 2020 |
| Kabled Limited | Health & social care | 2023 |
| Kahf Developers Ltd | Construction | 2010 |
| Kahf Enterprises Limited | Professional & scientific | 2015 |
| Kahf Living Limited | Real estate | 2025 |
| Kaia Bihani Homes Limited | Real estate | 2025 |
| Kairos Clean Ltd | Administrative & support | 2026 |
| Kaiyana Jewellery Ltd | Wholesale & retail | 2024 |
| Kajon Services Ltd | Health & social care | 2015 |
| KAL Consulting Ltd | Information & communication | 2024 |
| Kaleidoscope Travel Limited | Administrative & support | 2008 |
| KAMI11 Ltd | Construction | 2019 |
| Kamilari Ltd | Wholesale & retail | 2022 |
| Kamlesh Chanan Ltd | Extraterritorial | 2024 |
| Kamlesh Kaur Chanan Ltd | Extraterritorial | 2024 |
| Kanbi Sports Group Ltd | Arts & recreation | 2026 |
| Karina Fire Ltd | Administrative & support | 2016 |
| Karons Smile Clinic Limited | Health & social care | 2015 |
| Kaspion Consulting Limited | Information & communication | 2026 |
| Katan 2215 Ltd | Education | 2023 |
| Kava Lights Limited | Wholesale & retail | 2023 |
| Kavitron Services Limited | Health & social care | 2015 |
| Kaycee Limited | Professional & scientific | 2025 |
| Kayleigh's Boutique Limited | Other services | 2014 |
| Kayley Bear Limited | Hospitality | 2021 |
| Kayoworld Ltd | Wholesale & retail | 2009 |
| KC Kossakowski Construction Ltd | Construction | 2016 |
| KC Surveying Ltd | Professional & scientific | 2019 |
| KD Plumbing & Heating Limited | Construction | 2016 |
| KD Specialist Ltd | Construction | 2017 |
| KDL Express Ltd | Wholesale & retail | 2017 |
| Kebabs ARE US Ltd | Hospitality | 2026 |
| Keemfai Ltd | Professional & scientific | 2018 |
| Keeping the Books Ltd | Professional & scientific | 2022 |
| Keils House Ltd | Real estate | 2025 |
| Kelly & Sons Properties Limited | Real estate | 2026 |
| Kengland Ltd | Wholesale & retail | 2026 |
| Kennybee Limited | Health & social care | 2022 |
| Kenoye Limited | Information & communication | 2019 |
| Kent Boiler Solutions Ltd | Construction | 2025 |
| Kent Chinese Takeaway Ltd | Hospitality | 2022 |
| Kent P.E.O Solutions Ltd | Professional & scientific | 2018 |
| Kenwel Electricals Trading Ltd | Manufacturing | 2025 |
| Kerad Lighting Limited | Wholesale & retail | 2024 |
| Keshavprit Ltd | Wholesale & retail | 2024 |
| KEV Air Ltd | Construction | 2013 |
| Kevillon Tech. Services Ltd | Construction | 2011 |
| Key Skills Sports Ltd | Education | 2019 |
| Kfat Limited | Health & social care | 2018 |
| KH Asian Foods Ltd | Hospitality | 2024 |
| Khade Properties Limited | Real estate | 2024 |
| Khairluxury Ltd | Other services | 2026 |
| Khaja Ghar Limited | Hospitality | 2022 |
| Khoorbhoor Property Limited | Real estate | 2022 |