When someone buys shares in a corporation that owns an entire apartment building, what is this arrangement called?

In the context of real estate ownership, when someone buys shares in a corporation that owns an entire apartment building, this arrangement is called a cooperative. In a cooperative, residents do not own their individual units outright; instead, they own shares in the corporation that collectively owns the entire property. These shares give residents the right to occupy a specific unit and participate in the governance of the cooperative through a board of directors.

This structure allows for shared ownership and management of the property, creating a community among residents who have a vested interest in the maintenance and operation of the building. The cooperative model contrasts with condominiums, where individuals own their specific units and have individual titles, and partnerships or joint ventures, which are typically formed for business ventures rather than residential ownership. Thus, the correct answer accurately reflects the nature of the ownership structure described in the question.