The Collectivité of Saint-Martin has been the majority shareholder of the Société d'Économie Mixte de Saint-Martin (Semsamar) since its creation in 1985.

Semsamar is a real estate developer and operator present in Saint-Martin, Guadeloupe, Guyana and Martinique which offers a wide range of activities:

- urban planner

- social or private landlord

- promoter-developer

- builder of housing, business real estate or public facilities

- real estate developer

- developer and manager of tourist facilities.

Semsamar notably offers a housing rental service, including social housing, for all budgets in Saint-Martin.