| Mackay Contracting Limited | Construction | 2023 |
| Maclean Project Services Limited | Professional & scientific | 2012 |
| Maclennan Coaches Limited | Transport & logistics | 2014 |
| Maclennan Garage Services Limited | Wholesale & retail | 2014 |
| Macleod & Buchanan Limited | Construction | 2015 |
| Macleod & Macleod Engineering Ltd | Professional & scientific | 2023 |
| Macleod & Macleod Ltd | Wholesale & retail | 2020 |
| Macleod Architecture Limited | Professional & scientific | 2017 |
| Macleod Car Sales Limited | Wholesale & retail | 2025 |
| Macleod Hospitality Group Limited | Financial services | 2016 |
| Macleod Properties Limited | Real estate | 2001 |
| Macmillan Consulting Limited | Professional & scientific | 2025 |
| Macneil Fishing Limited | Agriculture & fishing | 2018 |
| Macphee Plumbing and Heating Ltd | Construction | 2025 |
| Mangersta Croft Holidays Ltd | Hospitality | 2019 |
| Manor and Castle Community Trust Ltd | Other services | 2019 |
| Manor Hotel (Stornoway) Holdings Limited | Professional & scientific | 2010 |
| Melbost & Branahuie Development Trust Ltd | Extraterritorial | 2019 |
| Melbost Branahuie Community Energy Ltd | Energy | 2018 |
| Mhik Holdings Limited | Transport & logistics | 2012 |
| Mini Golf Island Ltd | Arts & recreation | 2024 |
| MJC Inspection and Design Limited | Professional & scientific | 2006 |
| MNM Hair Design Ltd | Administrative & support | 2012 |
| Morrison Engineering Ltd | Professional & scientific | 2017 |
| Morrison Masonry Ltd | Manufacturing | 2024 |
| Neil Mackay & Co Ltd | Construction | 2005 |
| Nessram Ltd | Professional & scientific | 2014 |
| Newton Gateway Limited | Construction | 2019 |
| NO.9 Coffee Shop Ltd | Hospitality | 2020 |
| Norman Mackenzie Kitchens & Bathrooms Ltd | Construction | 2013 |
| Norrie's Motor Services Limited | Wholesale & retail | 2017 |
| Norserv FM Ltd | Administrative & support | 2014 |
| North Uist Engineering Services Ltd | Extraterritorial | 2016 |
| North Western Electrical Services Ltd | Construction | 2026 |
| Northern Star Fishing Limited | Agriculture & fishing | 2014 |
| Office 121 Limited | Professional & scientific | 2009 |
| Ontime IT & Comms Limited | Information & communication | 2011 |
| ORB Limited | Manufacturing | 1983 |
| ORB Tweed Limited | Manufacturing | 1986 |
| Orbis Property Holdings Ltd | Construction | 2024 |
| ORR Group Ltd. | Construction | 2023 |
| Outer Hebrides Fisheries Trust | Professional & scientific | 2006 |
| Outer Hebrides Social Economy Partnership CIC | Other services | 2010 |
| P & J Furey Ltd | Wholesale & retail | 2015 |
| Parts+ Stornoway Limited | Manufacturing | 2020 |
| Peat and Diesel Limited | Arts & recreation | 2019 |
| Peat Smoked Coffee Limited | Manufacturing | 2025 |
| Pegasus Marine Surveys Limited | Administrative & support | 2016 |
| Pj's Hair Design Limited | Other services | 2001 |
| Point and Sandwick Battery Ltd | Extraterritorial | 2021 |
| Point and Sandwick Power Limited | Energy | 2009 |
| Point Contract Services Limited | Professional & scientific | 2023 |
| Port of Ness Harbour Limited | Other services | 1999 |
| Prestige Decorators STY Ltd | Construction | 2026 |
| Pure Isles Skincare Limited | Manufacturing | 2025 |
| Purple TV Limited | Information & communication | 2012 |
| Pursuit Hebrides Adventure Island Ltd. | Arts & recreation | 2015 |
| QHZ Ltd | Hospitality | 2018 |
| R and K Catering Limited | Hospitality | 2024 |
| Raincloud Scotland Ltd. | Extraterritorial | 2021 |
| Rautela & Rathaurstornoway Limited | Hospitality | 2025 |
| Reefnet Ltd | Information & communication | 2009 |
| REM (Scotland) Limited | Professional & scientific | 2023 |
| Revive Arabic Ltd | Education | 2026 |
| RMK Offshore Ltd | Professional & scientific | 2017 |
| RMM Maritime Limited | Professional & scientific | 2018 |
| Royal Hotel (Stornoway) Holdings Limited | Professional & scientific | 2010 |
| Rural Nations (Scotland) CIC | Information & communication | 2014 |
| S & E Construction (Highland) Ltd | Construction | 2024 |
| S & SG Ltd | Agriculture & fishing | 2003 |
| Sandwick Bay Candles Limited | Manufacturing | 2018 |
| Sandwick Bay Hotel Limited | Hospitality | 2008 |
| Sandwick East Community Energy Ltd | Energy | 2018 |
| Sandwick East Street & Lower Sandwick Trust Ltd | Other services | 2019 |
| Sandwick Land Trust Ltd | Extraterritorial | 2022 |
| Sandwick North Community Energy Ltd | Energy | 2018 |
| Sandwick North Street Trust Ltd | Other services | 2019 |
| Saorsa 27 Property Ltd | Real estate | 2019 |
| SBA + at Architects + Designers Ltd | Professional & scientific | 2026 |
| SBA Architects Limited | Professional & scientific | 2008 |
| Scaristavore Crofting Trust Limited | Agriculture & fishing | 1999 |
| Seaforth Hotel (Stornoway) Holdings Limited | Professional & scientific | 2010 |
| Seaforth Plumbing & Heating Ltd | Construction | 2026 |
| Seaglass Pictures Limited | Information & communication | 2022 |
| Seaqurefarming 1 Limited | Agriculture & fishing | 2024 |
| Seaqurefarming 2 Limited | Agriculture & fishing | 2024 |
| Seaqurefarming 3 Limited | Agriculture & fishing | 2024 |
| Seaqurefarming 4 Limited | Agriculture & fishing | 2024 |
| Seaqurefarming 5 Limited | Agriculture & fishing | 2024 |
| Seaqurefarming 6 Limited | Agriculture & fishing | 2025 |
| Seas the Catch Limited | Wholesale & retail | 2018 |
| Severne Limited | Information & communication | 2010 |
| Sgoil-Chiùil Steòrnabhaigh/Stornoway School of Traditional Music C.I.C. | Education | 2026 |
| Sgoiltean URA Investments Limited | Professional & scientific | 2007 |
| Sgoiltean URA LLP | | 2007 |
| Shaun Macdonald Electrical Ltd | Construction | 2024 |
| Sheshader Development Company | Professional & scientific | 2019 |
| Silver Chord Ltd | Agriculture & fishing | 2017 |
| SMK Roofing Ltd | Construction | 2025 |
| Solair SY Ltd | Hospitality | 2026 |