We examine bargaining in a dynamic context where exchange between two parties affects the potential surplus from future trade. In this setting traders negotiate current contracts anticipating the impact of their agreement on future exchanges. We show that in growing environments these dynamic considerations will often ameliorate bargaining inefficiencies associated with private information and facilitate exchange as both parties cooperate to nurture the relationship. In contrast, we find that in declining environments dynamic considerations will often exacerbate bargaining inefficiencies and hinder trade, as both parties are hesitant to let the relationship mature. These findings have implications for preferences to form long-lived relationships.