National Trust | National Trust for Places of Historic Interest or Natural Beauty | Wellcome Trust | National Trust for Historic Preservation | National Trust of Australia | Wellcome Trust Sanger Institute | The Prince's Trust | BBC Trust | Leverhulme Trust | Durrell Wildlife Conservation Trust | Devon Wildlife Trust | Moorfields Eye Hospital NHS Foundation Trust | Metropolitan Bank and Trust Company | The Royal Marsden NHS Foundation Trust | Terrence Higgins Trust | Saccharine Trust | Prince's Trust | Pilgrim Trust | NHS trust | New Zealand Historic Places Trust | National Book Trust | J. Paul Getty Trust | Trust law | Teenage Cancer Trust | Social Security Trust Fund | Russell Trust Association | Police Memorial Trust | Karachi Port Trust | Ironbridge Gorge Museum Trust | Global Crop Diversity Trust |
Prior to his political career, Marcoux held several important administration positions including vice-president for the Bank of Canada, Laurentian Bank and Trust La Laurentienne, in the early 1980s as well as key positions at the province-run "Société général de financement du Quebec" (SGF) as well as private supermarket Provigo.