| A Bruce (Building) Ltd | Construction | 2003 |
| Alan Mackie and Partners | | 1989 |
| Birkenhill Computing Services Limited | Real estate | 1980 |
| BLP 2001-58 Limited | Professional & scientific | 2001 |
| Bylbster Farms | | 1989 |
| Caithness Cabs 65 Ltd | Transport & logistics | 2024 |
| Caithness Fish Salesmen's Association Limited | Wholesale & retail | 1992 |
| Caithness Seacoast Ltd | Transport & logistics | 2005 |
| Colin Chessor Limited | Wholesale & retail | 2005 |
| Computafix (Wick) Ltd. | Professional & scientific | 2003 |
| D Steven & SON Holdings Limited | Financial services | 2025 |
| Daca Fishing Ltd | Agriculture & fishing | 2019 |
| Dolye Ltd | Construction | 2025 |
| Dounreay Site Restoration Limited | Extraterritorial | 2006 |
| Dunbeath Partnership | | 1997 |
| FAR North Aviation Limited | Transport & logistics | 2007 |
| Flex Hill Ltd | Energy | 2005 |
| Forsie Farm Ltd | Agriculture & fishing | 2003 |
| G Anderson Electrical Ltd | Construction | 2004 |
| George Campbell (Farmers) Limited | Agriculture & fishing | 1960 |
| George Durran and SON, Limited | Wholesale & retail | 1921 |
| George Mcbeath Limited | Wholesale & retail | 2002 |
| Gills Harbour Ltd | Agriculture & fishing | 2009 |
| Grudgehouse Farms | | 1990 |
| Gunns (Lybster) Limited | Professional & scientific | 1972 |
| Hazel Hoatsen and Partners | | 1992 |
| Hillhead Property Development Limited | Real estate | 2003 |
| Hook Technical Ltd | Professional & scientific | 2022 |
| Hunter's Promotions Limited | Manufacturing | 2003 |
| J & E Mowat | | 1995 |
| James Gunn & Partner | | 2001 |
| John Anderson & Partners | | 1988 |
| John Gunn & Sons Limited | Construction | 1953 |
| John Gunn and Sons (Holdings) Limited | Professional & scientific | 2001 |
| John Hood & Son(Sculptors)Limited | Manufacturing | 1976 |
| John O'Groats Ferries Limited | Transport & logistics | 1993 |
| Joscom Consultancy Ltd | Information & communication | 2017 |
| K.A. Budge Limited | Construction | 2006 |
| Lower Reiss Farms | | 1992 |
| M Cowie Solutions Ltd | Construction | 2022 |
| Mackays Garage Limited | Wholesale & retail | 1986 |
| Netherton West Farms | | 1989 |
| Nitraminos Limited | Information & communication | 2007 |
| O'Brien Construction Limited | Construction | 1972 |
| Ormlie Garage Ltd | Wholesale & retail | 2004 |
| Plancore Ltd | Professional & scientific | 2026 |
| Plowman's Carpets Ltd | Wholesale & retail | 2003 |
| Queen's Hotel (Wick) Ltd | Hospitality | 2004 |
| Quoys of Reiss Farms | | 1991 |
| Reid & Fraser Ltd. | Professional & scientific | 1999 |
| Robertsons of Tain (North) Limited | Wholesale & retail | 2006 |
| Sandy Macgregor Limited | Construction | 2004 |
| Seal House Sunrise Ltd | Hospitality | 2025 |
| Seescai Ltd | Professional & scientific | 2017 |
| Sheigra Fishing Company Ltd | Agriculture & fishing | 2006 |
| Sibster Farms | | 1988 |
| Sinclair Bay Lobster Company Limited | Agriculture & fishing | 2002 |
| Speedy Skip Hire Limited | Water & waste | 1983 |
| Steven Blackwood Fencing Limited | Administrative & support | 2003 |
| T.D. Gall Limited | Construction | 1994 |
| THE Wick Society | Arts & recreation | 2004 |
| Thrumster Estate Limited | Real estate | 1935 |
| Thurso Planning Services (Scotland) Ltd | Administrative & support | 2007 |
| Toftinghall Limited | | 1988 |
| W & D Ross Limited | Construction | 2002 |
| W & G Coghill and Partners | | 1989 |
| W Gunn Limited | Real estate | 2002 |
| W. & a. Geddes Limited | Wholesale & retail | 1991 |
| Watten Farms | | 1989 |
| Whitesnowcrystal Limited | Agriculture & fishing | 2003 |
| William Dunnet & Company Limited | Wholesale & retail | 1957 |
| Windy House Limited | Agriculture & fishing | 2006 |