| Marsten Developments (Worcester) Limited | Construction | 1974 |
| Marston Mews Management Company Limited | Administrative & support | 2016 |
| Martech Engineering Services Limited | Professional & scientific | 2017 |
| Martel Court Residents Association Ltd | Households | 2025 |
| Martin Addison OIL Boiler Services Ltd | Construction | 2024 |
| Martin Bruno Construction Ltd | Construction | 2014 |
| Martin Morris Technical Services Ltd. | Wholesale & retail | 2006 |
| Martin Price & Company Limited | Extraterritorial | 2003 |
| Martins Construc Limited | Construction | 2026 |
| Martley Court Barns Management Company Limited | Real estate | 2000 |
| Martley Stone Ltd | Wholesale & retail | 2025 |
| Martley Web Mesh | Information & communication | 2005 |
| Martucci Limited | Administrative & support | 2004 |
| Marvellous Mixes Ltd | Manufacturing | 2017 |
| Maryland Resources Ltd | Other services | 2019 |
| MAS Health Ltd | Health & social care | 2022 |
| Mase J Services Ltd | Construction | 2025 |
| Mason Closing Ltd | Professional & scientific | 2026 |
| Mason Pearce Holdings Limited | Financial services | 2026 |
| Masons Wadborough Ltd | Hospitality | 2021 |
| Masquerade Fabrics Limited | Wholesale & retail | 2005 |
| Master Plan Focus Limited | Professional & scientific | 2021 |
| Masterclad Systems Ltd | Wholesale & retail | 2024 |
| MAT Couriers Limited | Transport & logistics | 2020 |
| Mateiall. Ltd | Transport & logistics | 2022 |
| Materials Engineering & Testing Ltd | Professional & scientific | 2014 |
| Mathias Construct Limited | Construction | 2026 |
| Matrixity Limited | Education | 2022 |
| Matt Tally Player Development CIC | Education | 2023 |
| Matthann Ltd | Administrative & support | 2007 |
| Matthew Day Event Management Ltd | Administrative & support | 2013 |
| Matthew North Limited | Information & communication | 2008 |
| Matthew Squire & Company Limited | Professional & scientific | 2018 |
| Matthew Squire Consulting Limited | Extraterritorial | 2023 |
| Matthews & Co. Exterior Cleaning Ltd | Administrative & support | 2026 |
| MAV Consulting Services Limited | Wholesale & retail | 2026 |
| Mavex Property Group Limited | Financial services | 2025 |
| Mavex Property Investment Limited | Real estate | 2025 |
| MAW Project Services Ltd | Information & communication | 2026 |
| MAX Video Productions Ltd | Information & communication | 2022 |
| MAX Whitney Distillers Limited | Manufacturing | 2024 |
| Maxila Limited | Real estate | 2026 |
| Maxim Industries Limited | Wholesale & retail | 1991 |
| Maxim Property (Worcester) Ltd | Real estate | 2024 |
| Maxim Security Installations Limited | Extraterritorial | 2025 |
| Maximus Aequus Ltd | Extraterritorial | 2019 |
| Maximus Blackpole Limited | Real estate | 2021 |
| Maximus Cheltenham Limited | Real estate | 2022 |
| Maximus Group Limited | Real estate | 2002 |
| Maximus Island Ltd | Real estate | 2023 |
| Maximus Land Limited | Extraterritorial | 2011 |
| Maximus Redditch Limited | Real estate | 2021 |
| Maximus Strategic Bromsgrove Limited | Real estate | 2007 |
| Maximus Strategic Chipping Sodbury LLP | | 2009 |
| Maximus Strategic Land Limited | Real estate | 2009 |
| Maximus Strategic Stafford LLP | | 2009 |
| MAY Hill Limited | Professional & scientific | 2011 |
| Mayazi Food and Beverages Limited | Hospitality | 2025 |
| Maybeck Collections Limited | Professional & scientific | 2000 |
| Mayfield Resources Ltd | Other services | 2019 |
| Mayfly Project and Programme Management Limited | Professional & scientific | 2019 |
| Mayhouse Finance Limited | Administrative & support | 2009 |
| Mayo Business Services Ltd | Financial services | 2021 |
| Mayodelh Limited | Wholesale & retail | 2024 |
| Mayura News Agent Limited | Wholesale & retail | 2015 |
| Mayura Property Investment Ltd | Real estate | 2022 |
| Mayvn Ltd | Wholesale & retail | 2023 |
| Mazeon Living Ltd | Real estate | 2026 |
| MB Coldstores Ltd | Construction | 2017 |
| MB Treecare & Grounds Maintenance Ltd | Administrative & support | 2022 |
| MBG 21 Watermark Limited | Households | 2024 |
| Mbolo Life Style Limited | Professional & scientific | 2015 |
| MC Colours Ltd | Manufacturing | 2024 |
| MC Studios Limited | Professional & scientific | 2024 |
| MC2Z Ltd | Health & social care | 2023 |
| Mcallister Productions Ltd | Information & communication | 2019 |
| MCB Electronics Ltd | Wholesale & retail | 2011 |
| Mcbreen Enviro UK Limited | Water & waste | 2023 |
| MCC Transport Ltd | Transport & logistics | 2023 |
| Mccarthy Wealth Management Limited | Financial services | 2011 |
| Mccreadie's Limited | Professional & scientific | 1995 |
| Mcgloin Electrical Limited | Construction | 2002 |
| Mckenna Thomas Orthopaedics Ltd | Health & social care | 2018 |
| Mcmahon & Sons Ltd | Construction | 2023 |
| Mcminn Developments Ltd | Real estate | 2008 |
| Mcminn Property Investments Limited | Real estate | 2018 |
| Mcphee Holdings Limited | Wholesale & retail | 2020 |
| MD Bespoke Carpentry and Building Ltd | Construction | 2008 |
| Md's Edge Ltd | Other services | 2023 |
| MDA Civils Ltd | Construction | 2026 |
| MDA Groundworks Limited | Construction | 2017 |
| Mdavision Ltd | Transport & logistics | 2026 |
| Mdnm Consultancy Services Limited | Professional & scientific | 2020 |
| Mdpharm Ltd | Wholesale & retail | 2025 |
| MDR Athlete Development Ltd | Education | 2025 |
| MDS Property Developments Ltd | Construction | 2024 |
| ME & My Friend Designs Ltd | Wholesale & retail | 2010 |
| Meadow Traders Ltd | Professional & scientific | 2019 |
| Meadowview (Worcester) Ltd | Construction | 2021 |
| Meat & Treatz Ltd | Hospitality | 2025 |