| Michaela 081108 Ltd | Transport & logistics | 2021 |
| Micro Trench Ltd | Construction | 2022 |
| Microcore Ltd. | Information & communication | 1999 |
| Microspan Ltd | Arts & recreation | 2007 |
| Microtensor Limited | Manufacturing | 2023 |
| Midcontinent INS Co Ltd | Wholesale & retail | 2018 |
| Middlemiss Travel Limited | Administrative & support | 2025 |
| Middleton Panels & Paint Limited | Wholesale & retail | 2022 |
| Mideyah Stays Ltd | Real estate | 2023 |
| Midwifery Expert Witness Limited | Health & social care | 2018 |
| Mighty Oaks Little Acorns Limited | Education | 2017 |
| MIH Films Limited | Information & communication | 2014 |
| MIH Group Holdings Ltd | Real estate | 2021 |
| Miju Wools Ltd | Wholesale & retail | 2011 |
| Mike Adams Ltd | Financial services | 2013 |
| Mike Burris Flooring Limited | Wholesale & retail | 2007 |
| Mikel Folley Ltd | Health & social care | 2014 |
| MIKEY1BUC Productions Limited | Information & communication | 2025 |
| Mila Investment Group Ltd | Financial services | 2024 |
| Milaku Ltd | Wholesale & retail | 2019 |
| Mileone Driving School Ltd | Education | 2026 |
| Miles Griffon Limited | Professional & scientific | 2014 |
| Miles Mann Limited | Wholesale & retail | 2008 |
| Miles Mann Partnership LLP | | 2013 |
| Miletus Consultancy Limited | Professional & scientific | 2026 |
| Mill Place Management Limited | Households | 2006 |
| Millbrook Flat Management Limited | Real estate | 2006 |
| Millend Mill Eastington Management Limited | Households | 2015 |
| Millham Ltd | Construction | 2026 |
| Miloby Limited | Wholesale & retail | 2021 |
| Milq Ltd | Information & communication | 2025 |
| Mimmo Studios Limited | Wholesale & retail | 2021 |
| Mimosa Hair Ltd | Other services | 2024 |
| Mind Minder Limited | Information & communication | 2022 |
| Mind Over Performance CIC | Education | 2026 |
| Mindbody Synergy CIC | Education | 2025 |
| Minghe Holding Limited | Hospitality | 2026 |
| Minsterworth Court Limited | Financial services | 2021 |
| Mint Must Have Ltd | Wholesale & retail | 2019 |
| Mintcarz Ltd | Wholesale & retail | 2025 |
| Miracle 1 Services Ltd | Water & waste | 2025 |
| Mirakem UK Limited | Wholesale & retail | 2026 |
| Miri Housing Ltd | Extraterritorial | 2022 |
| Miriarto Communications Limited | Professional & scientific | 2023 |
| Mirus Consultancy Limited | Professional & scientific | 2015 |
| Mirus Energy Ltd | Construction | 2019 |
| Mirus Homes (SW) Ltd | Real estate | 2024 |
| Mirus Property Services Ltd | Administrative & support | 2022 |
| MIS Property Ltd | Hospitality | 2022 |
| Misco Investment Ltd | Real estate | 2024 |
| Miscotech Ltd | Information & communication | 2024 |
| Mispro Cleaning Ltd | Administrative & support | 2025 |
| Miss Beauty Salon Ltd | Other services | 2024 |
| Mission Insight Ltd | Information & communication | 2023 |
| Mister's Cafe Ltd | Hospitality | 2019 |
| Mistletoe Properties Ltd | Construction | 2026 |
| Misty to Clear Glos Ltd | Administrative & support | 2020 |
| Mitchell & Williams Limited | Other services | 2016 |
| Mitha Investments Ltd | Hospitality | 2022 |
| Mithra Designs Limited | Wholesale & retail | 2011 |
| Mitre Ltd | Construction | 2025 |
| Mitsuru Technologies Ltd | Information & communication | 2025 |
| MJ Home & Building Improvements Ltd | Construction | 2020 |
| MJ Rowley Ltd | Construction | 2025 |
| MJ2P Ltd | Information & communication | 2020 |
| MJB Beard Ltd | Construction | 2005 |
| Mjbc Ltd | Professional & scientific | 2025 |
| Mjbcargo Ltd | Transport & logistics | 2024 |
| Mjboon Electrical Ltd | Construction | 2021 |
| Mjcarter Plastering Limited | Construction | 2019 |
| MJM Carpentry & Joinery Ltd | Manufacturing | 2020 |
| MJP Construction Solutions Ltd | Construction | 2026 |
| MJP Homes Coaching & Training Limited | Education | 2024 |
| MJR Training Consultancy Ltd | Professional & scientific | 2019 |
| MJS Information Consulting Ltd | Information & communication | 2007 |
| MJS Lawn Care Limited | Administrative & support | 2017 |
| MK Haulage Services Limited | Transport & logistics | 2026 |
| MK Production Services Ltd | Administrative & support | 2021 |
| MK Tech Labs Ltd | Information & communication | 2025 |
| MK1 Properties Ltd | Real estate | 2024 |
| Mksdeals Limited | Wholesale & retail | 2023 |
| Ml&D Project Limited | Wholesale & retail | 2020 |
| Mlllf Ltd | Real estate | 2025 |
| MM Private Ltd | Wholesale & retail | 2023 |
| Mmam Trading Ltd | Wholesale & retail | 2024 |
| MMK Construction Ltd | Construction | 2020 |
| MMK Prestige Ltd | Real estate | 2022 |
| MML World Services Ltd | Transport & logistics | 2024 |
| Mnadee Ltd | Transport & logistics | 2022 |
| MO PI Cleaning Company Ltd | Other services | 2022 |
| Mobile Care Accessories Ltd | Manufacturing | 2026 |
| Mobile Media Blasting Ltd | Administrative & support | 2021 |
| Mobile Media Blasting Residential Ltd | Administrative & support | 2024 |
| Mobile Media Blasting Washing Ltd | Administrative & support | 2024 |
| Mobile Phone Gloucester Ltd | Wholesale & retail | 2026 |
| Mobile REP Store Limited | Wholesale & retail | 2021 |
| Mobile Repairs Technicians Ltd | Other services | 2023 |
| Mobility 1ST Ltd | Manufacturing | 2023 |
| Mobysure Ltd | Information & communication | 2012 |
| Mode Mens Barber Shop Ltd | Other services | 2019 |