| Marathon Property Ayrshire Ltd | Real estate | 2025 |
| Marcus Gourmet Ltd | Hospitality | 2023 |
| Marqglen Group Limited | Financial services | 2000 |
| Marqglen Limited | Real estate | 1987 |
| Marqglen Properties Limited | Real estate | 2000 |
| Marth Ltd | Construction | 2021 |
| Mauchline Road 1955 Limited | Extraterritorial | 2015 |
| Mcallister Transport Ltd | Transport & logistics | 2016 |
| Mccallums Custom Truckstyling LLP | | 2022 |
| Mccreath HV Engineering Ltd | Construction | 2019 |
| Mcdougall M&E Ltd | Construction | 2023 |
| Mcmillan of Scotland Ltd | Manufacturing | 2018 |
| Mcmillans Cafe Ltd | Hospitality | 2020 |
| Mcpheators Mechanical Ltd | Wholesale & retail | 2023 |
| Mercat Finance (Ayrshire) Limited | Financial services | 2012 |
| Merlin Park Retail Limited | Wholesale & retail | 2018 |
| MF Ramsey Ltd | Manufacturing | 2020 |
| Millacre Developments (Scotland) Limited | Construction | 2006 |
| Millaniel Boutique LLP | | 2026 |
| Millar Aviation Services Ltd | Professional & scientific | 2026 |
| Millar Electrics Holdings Limited | Professional & scientific | 2022 |
| Millar Electrics Limited | Construction | 1992 |
| Misurki Ltd | Wholesale & retail | 2023 |
| Mitchell Construction (Scotland) Ltd | Construction | 2021 |
| MJB Hastie Ltd | Construction | 2018 |
| Moogal Holdings Limited | Real estate | 2025 |
| Morton's Milk Ltd | Hospitality | 2020 |
| Muirkirk Breakfast Room Ltd | Hospitality | 2025 |
| Muirkirk Creatives Limited | Arts & recreation | 2024 |
| Muirkirk Enterprise Group | Information & communication | 2002 |
| Muirkirk Stores Limited | Wholesale & retail | 2017 |
| Muirkirk Superstore Ltd | Wholesale & retail | 2019 |
| Musson Contracting Limited | Agriculture & fishing | 2014 |
| Naturally YOU Holistic Therapies Ltd | Health & social care | 2025 |
| Nether Wellwood Farm Ltd | Agriculture & fishing | 2022 |
| Netherthird Community Development Group | Arts & recreation | 2010 |
| New Afton Ltd | Hospitality | 2022 |
| New Cumnock Development Trust | Other services | 2017 |
| Nexacorp Ltd | Wholesale & retail | 2025 |
| NEXTBUY1 Ltd | Wholesale & retail | 2025 |
| Nightfall Games Ltd | Manufacturing | 2018 |
| Nisu Business Limited | Wholesale & retail | 2025 |
| Normand Landscapes Limited | Construction | 2016 |
| North Shore Heritage LLP | | 2026 |
| O'Hare Logistics Group Ltd | Transport & logistics | 2026 |
| O'Kane Site Engineering Ltd | Construction | 2018 |
| Oakhouse Premier Sales & Lets Ltd | Real estate | 2023 |
| Ober Estate Ltd | Real estate | 2010 |
| Oberdarn Ltd | Real estate | 2015 |
| Oberdarn Wellwood Ltd | Real estate | 2019 |
| Old Tullymet Whisky Company Ltd | Wholesale & retail | 2017 |
| Omnicore Limited | Financial services | 2025 |
| Original Kebab Plus Cumnock Limited | Hospitality | 2025 |
| Otwells LLP | | 2024 |
| P Mclatchie Limited | Wholesale & retail | 2023 |
| Pagan Walk Investments 67 Ltd | Financial services | 2024 |
| Palmer & SON Groundworks Limited | Construction | 2022 |
| Peace of Mind Services Limited | Health & social care | 2016 |
| Periway Ltd | Hospitality | 2025 |
| Phoenix Wolf Retail Limited | Wholesale & retail | 2019 |
| Polquhairn Limited | Agriculture & fishing | 2012 |
| Practical Dairy Solutions Limited | Agriculture & fishing | 2014 |
| Prime Prep (Cumnock) Ltd | Hospitality | 2023 |
| Pro-Build (Ayrshire) Ltd | Construction | 2026 |
| Professional Legal Services Ltd | Financial services | 2016 |
| Proheavens Ltd | Wholesale & retail | 2025 |
| R M Johnston Ltd | Transport & logistics | 2021 |
| R Parkhurst Ltd | Financial services | 2015 |
| R Venton and Sons Ltd | Agriculture & fishing | 2024 |
| R&C Consulting Engineers Ltd | Professional & scientific | 2025 |
| R2 Total Solutions Ltd | Administrative & support | 2022 |
| RAB Lind Limited | Manufacturing | 2019 |
| RAD Project Management Ltd | Administrative & support | 2015 |
| Raeguard Electrical Ltd | Construction | 2025 |
| Rainbow Roots Creations Ltd | Manufacturing | 2025 |
| RB Woodlands Limited | Real estate | 2006 |
| RE Wind Turbine Services Ltd | Professional & scientific | 2025 |
| Rebro Group Ltd | Construction | 2023 |
| Regulus AI Ltd | Information & communication | 2026 |
| Regulus Group Ltd | Information & communication | 2026 |
| Requiro Security Solutions Ltd | Administrative & support | 2021 |
| Resolute Financial Advisers LLP | | 2013 |
| Respite NOW C.I.C. | Administrative & support | 2012 |
| RFB Enterprises Limited | Professional & scientific | 2007 |
| RHL(2021) Ltd | Real estate | 2021 |
| RJ Bramhall Group Ltd | Financial services | 2023 |
| Robin Walker Accountants LLP | | 2008 |
| ROJ AVA Scot Ltd | Other services | 2025 |
| Roma Fish & Chips Limited | Hospitality | 2022 |
| Rowe & Tudhope Ltd | Transport & logistics | 2022 |
| RS Services (Scotland) LLP | | 2013 |
| Rshm Ltd | Wholesale & retail | 2017 |
| Rtaw Holdings Ltd | Real estate | 2026 |
| Russell Bramhall Ltd | Health & social care | 2019 |
| Rwhb Ltd | Manufacturing | 2008 |
| RY Haultech Limited | Wholesale & retail | 2025 |
| S L Plumbing (Ayrshire) Ltd | Construction | 2018 |
| S S P (Ames Taping) Limited | Construction | 2016 |
| Sabri Properties Ltd | Real estate | 2022 |
| Sabri Retail Limited | Real estate | 2025 |