This paper determines how much scope capital market imperfections allow for autonomous policy in fixed and flexible exchange rate regimes. It discusses the experiences of Barbados, which maintains a fixed exchange rate, and Jamaica, with a flexible exchange rate. The Barbados results suggest there may be transactions costs, information costs, and switching costs that inhibit short-term capital movements to a much greater degree than is usually assumed. (Prepared for presentation at the Regional Programme of Monetary Studies Conference, Jamaica, November 23-26, 1994)