| Milestones Care Limited | Health & social care | 2013 |
| Miley Education Consultancy Limited | Education | 2017 |
| Milford (Nottingham) Ltd | Professional & scientific | 2025 |
| Milico Career Services Ltd | Education | 2023 |
| Milient Software Ltd | Information & communication | 2017 |
| Milisha Enterprises Limited | Real estate | 2024 |
| Military Community Network Group CIC | Professional & scientific | 2022 |
| Milkfish Ltd | Education | 2025 |
| Mill Entertainment Limited | Arts & recreation | 2023 |
| Mill House Developments (Lincoln) Limited | Households | 2011 |
| Mill Lane 1973 Limited | Extraterritorial | 2014 |
| Mill Motors Trade Cars Limited | Wholesale & retail | 2013 |
| Mill Property Holdings Limited | Professional & scientific | 2025 |
| Mill Transport (Yorkshire) Limited | Transport & logistics | 2010 |
| Millan Properties Ltd | Households | 2022 |
| Millbank Contract Solutions Limited | Professional & scientific | 2023 |
| Millberry Care Agency Limited | Health & social care | 2018 |
| Millbrook GP Limited | Financial services | 2022 |
| Millbrook Management Services Limited | Education | 1999 |
| Millbrook Village Management Limited | Administrative & support | 2011 |
| Millcourt Electrical Services Limited | Construction | 2015 |
| Millcroft Technology Limited | Manufacturing | 1997 |
| Millcroft Textiles Limited | Extraterritorial | 2002 |
| Millenium Limited | Information & communication | 2024 |
| Millenium SOL Limited | Professional & scientific | 1980 |
| Millennium Fire Ltd | Professional & scientific | 2019 |
| Miller and SON (Butchers) Limited | Wholesale & retail | 2001 |
| Miller Bennington Ltd | Hospitality | 2025 |
| Miller Freeman & Sons (Nottingham) Limited | Construction | 1988 |
| Miller Freeman Air Conditioning & Ventilation Ltd | Energy | 2024 |
| Miller Freeman Holdings Limited | Financial services | 2019 |
| Miller Group Ltd | Wholesale & retail | 2025 |
| Miller Mastery Ltd | Education | 2026 |
| Miller-Pate, Inc. | | 1988 |
| Millers Property Investments Ltd | Real estate | 2023 |
| Millership Estate Company Limited | Extraterritorial | 2014 |
| Millership Estate Property Investment Company Limited | Real estate | 2018 |
| Millfield Green Management Limited | Households | 2022 |
| Millhope Limited | Health & social care | 2018 |
| Millhouse Residences LLP | | 2023 |
| Milli & Brothers Ltd | Wholesale & retail | 2024 |
| Millie Estates Ltd | Real estate | 2023 |
| Millie Properties Ltd | Real estate | 2013 |
| Millie's Trinkets and Tiaras Limited | Manufacturing | 2011 |
| Millington Springs Care Centre Ltd | Health & social care | 2017 |
| Millionaire International Limited | Arts & recreation | 2018 |
| Millj Studios Limited | Wholesale & retail | 2025 |
| Millproducts Ltd | Professional & scientific | 2024 |
| Mills & Weave Ltd | Manufacturing | 2025 |
| Mills Oak Investments Ltd | Real estate | 2022 |
| Mills Warehouse Limited | Construction | 2023 |
| Millside Equestrian & Country Store Ltd | Wholesale & retail | 2008 |
| Millside Fresh Produce Ltd | Manufacturing | 2008 |
| Millspeed Engineering Limited | Manufacturing | 2006 |
| Millstone Logistics Limited | Transport & logistics | 2025 |
| Millward Partnership Holdings Limited | Financial services | 2020 |
| Milly Homes Ltd | Real estate | 2022 |
| Milly Moore Jewellery Ltd | Extraterritorial | 2015 |
| Milo 7 Limited | Wholesale & retail | 2019 |
| Milo Care Services Limited | Public administration | 2019 |
| Milo James Design Limited | Construction | 2025 |
| Milo Real Estate Ltd | Real estate | 2025 |
| Milos Restaurant & Social Limited | Hospitality | 2022 |
| Milot Strategy Ltd | Transport & logistics | 2014 |
| Milton Consulting (IT) Limited | Information & communication | 2021 |
| Milton Estates Group Ltd | Construction | 2022 |
| Milushi Bros Ltd | Real estate | 2023 |
| Milvus Investments Ltd | Real estate | 2021 |
| MIM Academy Ltd | Education | 2024 |
| Mimar Design Limited | Construction | 2009 |
| Mimas Bidco Limited | Financial services | 2021 |
| Mimas Topco Limited | Financial services | 2021 |
| Mime Industries Limited | Manufacturing | 2016 |
| Mimetic Labs Limited | Information & communication | 2025 |
| Mimex Healthcare (UK) Limited | Health & social care | 2024 |
| Mimi Internet and Technology Ltd | Wholesale & retail | 2024 |
| Mimi Kitchen Limited | Hospitality | 2022 |
| Mimigold Ltd | Health & social care | 2017 |
| Miminat Curated Creations Limited | Wholesale & retail | 2026 |
| Mimm Studios Limited | Wholesale & retail | 2022 |
| Mina Express Limited | Administrative & support | 2007 |
| Mind & Justice Psychology Services Ltd | Health & social care | 2026 |
| Mind and Mobility Limited | Health & social care | 2023 |
| Mind and Wellbeing Homecare Limited | Health & social care | 2023 |
| Mind Body Fit Ltd | Education | 2023 |
| Mind Body Fuel Ltd | Other services | 2019 |
| Mind Body Universe Ltd | Health & social care | 2025 |
| Mind Care & Support Ltd | Health & social care | 2020 |
| Mind Over Matter Fitness Limited | Other services | 2017 |
| Mindbody Centre Limited | Health & social care | 2003 |
| Mindcare Collective CIC | Education | 2025 |
| Mindcloud Erp.Ai Ltd | Information & communication | 2019 |
| Mindfish Limited | Administrative & support | 2015 |
| Mindfuel Games Limited | Information & communication | 2025 |
| Mindful First AID Limited | Health & social care | 2025 |
| Mindful Space of Healing Ltd | Health & social care | 2024 |
| Mindfully Better Limited | Information & communication | 2021 |
| Mindfulness Creative Hub Ltd | Arts & recreation | 2024 |
| Mindfulpath Ltd | Administrative & support | 2019 |
| Mindless Store Ltd | Wholesale & retail | 2024 |