| Mclean Projects & Events Ltd | Professional & scientific | 2014 |
| Meadowknowes Ltd | Real estate | 2023 |
| Melrose Butchers (Holdings) Limited | Financial services | 2024 |
| Melrose Chambers Coffee House Ltd | Hospitality | 2023 |
| Melrose Foot Care Limited | Health & social care | 2019 |
| Melrose Gastroenterology Limited | Health & social care | 2016 |
| Melrose Health Ltd | Health & social care | 2025 |
| Melrose Padel Club Limited | Arts & recreation | 2026 |
| Melrose Rugby Ltd | Arts & recreation | 2016 |
| Melrose Takeaway Ltd | Hospitality | 2023 |
| Melrose Trading Ltd | Other services | 2019 |
| Mentoring for Growth CIC | Administrative & support | 2021 |
| Meraki Hair & Makeup Studio Limited | Other services | 2020 |
| Michael Middlemiss Ltd | Real estate | 2019 |
| Microscotland (2015) Limited | Information & communication | 2015 |
| Mill Cottage Self Catering Limited | Hospitality | 2017 |
| Mindful Talent Limited | Professional & scientific | 2015 |
| Minerva Services (Scotland) Limited | Professional & scientific | 1995 |
| Mmis Store Limited | Wholesale & retail | 2017 |
| Molly's Angels CIC | Other services | 2025 |
| Morencourt Limited | Construction | 1989 |
| Murray Travel Limited | Administrative & support | 1983 |
| Murrow Wealth Management Limited | Professional & scientific | 2016 |
| MUS Developments Limited | Real estate | 2010 |
| Naughty Corner Events Limited | Hospitality | 2021 |
| Netherraw Forestry Limited | Agriculture & fishing | 2001 |
| Newhouse Johnston Partnership | | 1990 |
| Newstead Village Community Trust | Other services | 2020 |
| North Berwick Confectionery Ltd | Wholesale & retail | 2023 |
| North Berwick Properties Limited | Real estate | 2002 |
| Northfield Farming Ltd | Agriculture & fishing | 2016 |
| Oliver Engineering (Borders) Limited | Professional & scientific | 2013 |
| Omnirisk (UK) Ltd | Professional & scientific | 2017 |
| P&G Home Improvements Limited | Construction | 2012 |
| Palmer Campbell Limited | Construction | 2011 |
| PCW 2020 Ltd | Agriculture & fishing | 2024 |
| Phingask Estates Limited | Real estate | 2008 |
| Phingask Foreshore Limited | Financial services | 2024 |
| Pineappl. Limited | Manufacturing | 2017 |
| Pkjk Limited | Professional & scientific | 2023 |
| Pluto Logistics Solutions Ltd | Professional & scientific | 2025 |
| Pmgd Ltd | Professional & scientific | 2024 |
| Polly Productions Ltd | Information & communication | 2022 |
| Polwarth Lifetime Planning Ltd | Administrative & support | 2019 |
| Priorwood Construction Ltd | Construction | 2024 |
| Purple Moon Event Services Ltd | Professional & scientific | 2022 |
| Purpletwilight Limited | Professional & scientific | 2024 |
| R & K Marshall Limited | Agriculture & fishing | 2022 |
| R B Chambers Limited | Real estate | 2016 |
| R D Developments (Borders) Limited | Construction | 2017 |
| R&G Associates LLP | | 2006 |
| Raftery Property Group Ltd | Real estate | 2021 |
| Raimis Carpentry Limited | Manufacturing | 2022 |
| Raus Design Ltd | Professional & scientific | 2020 |
| Redmint Limited | Professional & scientific | 2006 |
| Reiver Events Ltd | Arts & recreation | 2022 |
| Reiver Travel Ltd | Administrative & support | 2018 |
| Reiver Veterinary Services Limited | Professional & scientific | 2021 |
| Richardson Roofing Services Ltd | Construction | 2024 |
| River Tweed Limited | Professional & scientific | 2022 |
| RM Scotland Ltd | Hospitality | 2026 |
| Robertson Timber Limited | Manufacturing | 2010 |
| Rodeco Ltd | Health & social care | 2021 |
| Rodgie Gallery & Print Limited | Wholesale & retail | 2014 |
| Roger Platfoot Polythene Limited | Wholesale & retail | 2002 |
| Rose + Julien Ltd | Professional & scientific | 2019 |
| Roulotte Retreat Limited | Hospitality | 2019 |
| RUG Repair Company Ltd | Other services | 2017 |
| Rural Renaissance Limited | Real estate | 2002 |
| S & W Homes Limited | Construction | 2020 |
| Saffet Tokgoz Ltd | Real estate | 2020 |
| Sallymc Consulting Ltd | Professional & scientific | 2022 |
| Sara + Sarah Smart Textile Design LLP | | 2018 |
| Sarah Dalrymple Consultancy Ltd | Hospitality | 2015 |
| SB Inspires LLP | | 2021 |
| SBB Entertainment Limited | Hospitality | 2022 |
| SBC Nominees Limited | Professional & scientific | 2014 |
| SC HK Holdco Limited | Financial services | 2009 |
| SC HK Opco Limited | Manufacturing | 1955 |
| Scan Tech NDT Limited | Professional & scientific | 2015 |
| Scotia Chiropractic Limited | Health & social care | 1992 |
| Scottish Borders Social Enterprise Chamber C.I.C. | Other services | 2005 |
| Serviceline (Scotland) Limited | Wholesale & retail | 2002 |
| Shepherd Stone Ltd | Information & communication | 2022 |
| Sherpa Walks Ltd | Arts & recreation | 2021 |
| Ship Inn Melrose Limited | Hospitality | 2022 |
| Silver Cellar Bar Ltd | Hospitality | 2020 |
| Sky-Pin Drones Ltd | Agriculture & fishing | 2017 |
| Springwood Arch Ltd | Extraterritorial | 2015 |
| SSJ Essential Services Limited | Health & social care | 2019 |
| ST Boswells Catering Limited | Hospitality | 2020 |
| ST Boswells Contracting Services Ltd | Administrative & support | 2017 |
| ST Boswells Fuels Limited | Manufacturing | 2009 |
| ST Boswells LLP | | 2006 |
| Stag Cameron Developments Ltd | Construction | 2018 |
| Studio Sloan Ltd | Information & communication | 2023 |
| Sunshine Real Estate Investments Ltd | Construction | 2023 |
| Surekill Limited | Agriculture & fishing | 2003 |
| Susan Cove Accountancy Limited | Professional & scientific | 2012 |
| Suzie Walker Catering Ltd | Hospitality | 2022 |