| Musgrave Estates Limited | Real estate | 2016 |
| Mushemi Properties Limited | Real estate | 2020 |
| Mushtaq & Sons Ventures Ltd | Wholesale & retail | 2025 |
| Mushtaq Sweets Cardiff Ltd | Wholesale & retail | 2022 |
| Music Industry Education LLP | | 2018 |
| Music Industry Group Limited | Education | 2014 |
| Music IS Everything CIC | Education | 2026 |
| Music Theatre Wales | Arts & recreation | 1993 |
| Musicalize Ltd | Arts & recreation | 2012 |
| Musicalize Touring Ltd | Arts & recreation | 2013 |
| Musicbox Studios Limited | Other services | 2007 |
| Muskan Living Limited | Real estate | 2024 |
| Muskari Ltd | Wholesale & retail | 2025 |
| Muskmeta Limited | Information & communication | 2021 |
| Muslim at Tech Limited | Information & communication | 2025 |
| Muslimah Outdoors CIC | Other services | 2024 |
| Musrau Limited | Wholesale & retail | 2018 |
| Must Homes Ltd | Hospitality | 2017 |
| Mustafa Polat Ltd | Wholesale & retail | 2025 |
| Mustafathetutor Ltd | Wholesale & retail | 2025 |
| Mustapand Ltd | Wholesale & retail | 2025 |
| Mustard Advisers Ltd | Professional & scientific | 2015 |
| Mustard Seed Resources Limited | Health & social care | 2025 |
| Mustard Yellow Motorsport Limited | Professional & scientific | 2013 |
| Muswaka Ltd | Health & social care | 2012 |
| Mutatio Strategic Ltd | Extraterritorial | 2024 |
| Mutercimco Translation Ltd | Professional & scientific | 2024 |
| Muti Products Ltd | Wholesale & retail | 2019 |
| Mutiny Kitchens Ltd | Hospitality | 2012 |
| Muuza Clothing Ltd | Wholesale & retail | 2026 |
| Muwati Limited | Wholesale & retail | 2021 |
| Muyi Foreign Trade Ltd | Wholesale & retail | 2024 |
| MUZ IRS Ltd | Information & communication | 2018 |
| Muzammil Mart Ltd | Wholesale & retail | 2026 |
| MV Ecomm ASS Ltd | Wholesale & retail | 2025 |
| MV Legends Ltd | Information & communication | 2019 |
| MV Partners Limited | Financial services | 2024 |
| MVC Residential Ltd. | Real estate | 2016 |
| MVD Enterprises Limited | Hospitality | 1997 |
| MVG Consultancy Ltd | Professional & scientific | 2013 |
| MVN Enterprises PVT Ltd | Arts & recreation | 2019 |
| Mvnc Ltd | Water & waste | 2019 |
| MVO Repair Ltd | Manufacturing | 2018 |
| MW & Sons Limited | Households | 2021 |
| MW AML Compliance Ltd | Professional & scientific | 2018 |
| MW Bradshaw (U.K.) Consulting Ltd | Professional & scientific | 2019 |
| MW Carpentry & Home Improvements Ltd | Manufacturing | 2021 |
| MW Corporate Ltd | Professional & scientific | 2021 |
| MW Industrial Refurb Ltd | Construction | 2015 |
| MW Studio Ltd | Wholesale & retail | 2014 |
| MW Syston Ltd | Information & communication | 2021 |
| MW TRE Limited | Administrative & support | 2018 |
| MW Windscreens Ltd | Wholesale & retail | 2025 |
| MW1605 Ltd | Hospitality | 2025 |
| Mwansa Food & Beverages Ltd | Manufacturing | 2015 |
| Mwft Holdings Limited | Professional & scientific | 2019 |
| MWG Y MÔR Ltd | Manufacturing | 2025 |
| MWH Heating & Plumbing Limited | Construction | 2014 |
| MWL Print Group Limited | Manufacturing | 1973 |
| Mwnci Climbing Limited | Wholesale & retail | 2025 |
| MWR Accountancy Services Ltd | Professional & scientific | 2025 |
| MWR Accountants Bristol Limited | Professional & scientific | 2017 |
| MWR Business Solutions Limited | Real estate | 2013 |
| MWS Real Estate Ltd | Real estate | 2021 |
| Mwstard Limited | Professional & scientific | 2016 |
| MWV Bikes Ltd | Wholesale & retail | 2020 |
| MX2 Technology Limited | Information & communication | 2018 |
| Mxgz Holdings Ltd | Other services | 2018 |
| MXK Ltd | Hospitality | 2020 |
| MXM Productions Ltd | Information & communication | 2021 |
| MXM Property Ltd | Real estate | 2025 |
| Mxnarch Ltd | Information & communication | 2020 |
| My Admission Card Ltd | Education | 2023 |
| My Apple Ltd | Administrative & support | 2016 |
| My ARCH1TECT Ltd | Construction | 2022 |
| My Asian Wedding Store Limited | Wholesale & retail | 2016 |
| My Bayley Ltd | Real estate | 2025 |
| My Beauty Limited | Other services | 2017 |
| My Beauty Professional Ltd | Other services | 2022 |
| My Best Product Ever Limited | Wholesale & retail | 2016 |
| My Brother and I Limited | Hospitality | 2010 |
| My Build (Bristol) Ltd | Financial services | 2024 |
| My Business Lynq Ltd | Information & communication | 2019 |
| My Cardiff Accountant Ltd | Professional & scientific | 2011 |
| My City Place Limited | Hospitality | 2017 |
| My Company Clothing Ltd | Wholesale & retail | 2011 |
| My Cornerstone Ltd | Construction | 2019 |
| My Cuppa Limited | Hospitality | 2025 |
| My Delivery Ltd | Information & communication | 2020 |
| My Developments, Home , Extension & Renovations Ltd | Construction | 2023 |
| My EDUC8ION | Education | 2025 |
| My EPC Checker Limited | Real estate | 2019 |
| My Exam Partner Ltd | Education | 2026 |
| My Family Estate Plan Limited | Professional & scientific | 2019 |
| My Fashion Craft Ltd. | Wholesale & retail | 2019 |
| My Fixes Ltd | Administrative & support | 2022 |
| My Football Hub Limited | Information & communication | 2019 |
| My Free Booking App Ltd | Information & communication | 2025 |
| My Global Product Limited | Wholesale & retail | 2025 |
| My Green CAB Ltd | Transport & logistics | 2017 |