We analyze the principle of comparative advantage when agents in the w
orld market are aware of the influence their individual supply exerts
on the equilibrium exchange rate of goods, We show that specialization
following comparative disadvantage can be an oligopoly equilibrium in
a Ricardian economy. Moreover, for a wide class of economies, it is t
he only one. Nonetheless, when the number of agents in each country in
creases without limit, the equilibrium in which specialization follows
comparative advantage again obtains.