| Hopes Cleaning Service Limited | Administrative & support | 2020 |
| HQR Technologies Limited | Information & communication | 1988 |
| Hydra Capital Limited | Information & communication | 2015 |
| Imperial Antiquity Ltd | Other services | 2024 |
| Import Refunds Limited | Administrative & support | 2026 |
| Industrial Property Management Limited | Professional & scientific | 2001 |
| Inhere Limited | Other services | 2017 |
| Interim Recruitment Solutions Limited | Administrative & support | 2021 |
| Intisars Jewellery Limited | Manufacturing | 2013 |
| J P R Medical Limited | Health & social care | 2017 |
| J.J. Moss & Sons Limited | Construction | 2004 |
| J.T. Westhorp Limited | Wholesale & retail | 1979 |
| Jakad Limited | Real estate | 2020 |
| James George Recruitment (Holdings) Limited | Financial services | 2021 |
| James George Recruitment Limited | Administrative & support | 2021 |
| Jarreo Limited | Professional & scientific | 2019 |
| Jerk and Juice Catering Limited | Hospitality | 2015 |
| Jmeg Properties Limited | Real estate | 2019 |
| Joanne Dawn Gurney Ltd | Extraterritorial | 2025 |
| Jordan Land LLP | | 2009 |
| Just Curious Club Ltd | Other services | 2023 |
| Kafecom Limited | Health & social care | 2003 |
| KAI Letting Limited | Real estate | 2014 |
| Kathmandu Link Limited | Manufacturing | 2012 |
| Kaytej Consulting Limited | Information & communication | 2018 |
| Kcmh Property Holdings Limited | Real estate | 2024 |
| KEM &TAN Ltd | Hospitality | 2022 |
| Key Environmental Solutions (Holdings) Limited | Financial services | 2014 |
| Kind & Co. (Builders) Limited | Construction | 1944 |
| KKI Properties Ltd | Construction | 2020 |
| Knowledgehandle Limited | Information & communication | 2010 |
| KOC Store Ltd | Wholesale & retail | 2019 |
| Kofisi Hospitality Group Limited | Administrative & support | 2014 |
| L33 Components Limited | Manufacturing | 2022 |
| Lancaster Homes Limited | Construction | 2006 |
| LDF Chicken Ltd | Hospitality | 2018 |
| LE Burger Express Limited | Hospitality | 2024 |
| LEA Valley Properties Limited | Real estate | 1989 |
| LEA Valley Residential Limited | Real estate | 2007 |
| Legacy & Co Holdings Ltd | Real estate | 2025 |
| Legacy & Co Holdings Ltd Limited | Real estate | 2025 |
| Legacy Business Centre 2 LLP | | 2007 |
| Leyton House Estates Ltd | Real estate | 2016 |
| Leyton Taxi Parts 11 Ltd | Wholesale & retail | 2022 |
| Leytonstone House Limited | Real estate | 2018 |
| Liberty-Izone Limited | Other services | 2003 |
| Lick Creative Limited | Professional & scientific | 2007 |
| Lictor Limited | Financial services | 2015 |
| Lime and Mint Ltd | Wholesale & retail | 2023 |
| Lime Tree and Sinnott Healthcare Ltd | Health & social care | 2006 |
| Lingerie Heaven Limited | Wholesale & retail | 2009 |
| Little Maintenance MAN Ltd | Households | 2021 |
| Littlemachineshop Limited | Wholesale & retail | 2015 |
| LJM Property Limited | Real estate | 2017 |
| LMO UK LLP | | 2006 |
| LMP Central Services Limited | Real estate | 2022 |
| LMP Development Properties Limited | Real estate | 2022 |
| LMP Investments Limited | Financial services | 2022 |
| LMP Properties & Logistics Limited | Real estate | 2022 |
| Lorena Baird Limited | Financial services | 2016 |
| LPB Homes Holdings Limited | Financial services | 2021 |
| LPB Homes Investment Limited | Real estate | 2021 |
| LPB Homes Limited | Construction | 2019 |
| Lumen House Limited | Real estate | 2020 |
| M J Works Ltd | Education | 2015 |
| M&M Investing Ltd | Real estate | 2020 |
| M&R Flooring & Logistics Ltd | Construction | 2023 |
| M.A.M.O & Services Ltd | Other services | 2016 |
| Mackinlay Properties Ltd | Real estate | 2022 |
| Madaster Services UK Limited | Information & communication | 2023 |
| Make Made Limited | Information & communication | 2014 |
| Management and Production Limited | Professional & scientific | 1996 |
| Mapp Consulting Limited | Real estate | 2007 |
| Marion Lichtig Limited | Other services | 2010 |
| Masa Technologies Group Ltd | Information & communication | 2025 |
| Matchstone Limited | Administrative & support | 2005 |
| Mattison Scaffolding Holdings Limited | Professional & scientific | 2018 |
| Mayra Property Services Ltd | Real estate | 2025 |
| MB Assured Consulting Ltd | Information & communication | 2006 |
| MB Assured Investments Limited | Real estate | 2016 |
| MBG Construction Limited | Construction | 2005 |
| Medina Consulting (UK) Limited | Administrative & support | 2016 |
| Medipharm Services Limited | Health & social care | 2015 |
| Mehkir Properties Limited | Real estate | 2020 |
| Merch Sphere Ltd | Wholesale & retail | 2025 |
| Mercy Smile Ltd | Wholesale & retail | 2025 |
| Metafont Limited | Manufacturing | 2022 |
| MF Consult Ltd | Professional & scientific | 2024 |
| MGH Construct Ltd | Construction | 2026 |
| Michael Kroyer Holdings Limited | Financial services | 2018 |
| Michael Kroyer Investments Limited | Financial services | 1964 |
| Mick Jeans Ltd | Wholesale & retail | 2021 |
| Mltp Investments Limited | Financial services | 2024 |
| Moco Star Limited | Wholesale & retail | 2025 |
| Morelands LLP | | 2007 |
| Morris DRY Cleaners Ltd | Other services | 2011 |
| Mottisfont Furniture Limited | Wholesale & retail | 2016 |
| Mount Pleasant Manor Limited | Construction | 2014 |
| Mountfield Building Group Limited | Construction | 1987 |
| Mountfield Holdings Limited | Financial services | 2021 |