Trade liberalization can have different effects when world markets are not perfectly competitive. The study looks at three scenarios: when a country intervenes in the market, when a private firm acts as a middleman, and when a producer-owned board controls exports. It shows that assuming perfect competition when there are market imperfections can lead to overestimating the impact of tariff reductions on prices and trade volume. In cases of monopoly and monopsony power, both importing and exporting countries may benefit more from direct transfers than from trade liberalization.