Governments have increasingly relied on exchange rate stabilization policies, specifically intervention operations in currency markets and capital controls, to offset external shocks. The focus on exchange rate stabilization is not limited to countries with pegged exchange rate regimes. Indeed, a number of countries that currently actively intervene in currency markets self-describe as floaters. The U.S. has responded by raising concerns that these policies amount to currency manipulation. Article IV of the IMF Articles of Agreement requires that members “avoid manipulating exchange rates” in order to gain an unfair competitive advantage over other members. Separately (since 1989) the U.S. Treasury must report to Congress biannually regarding whether individual trading partners are manipulating currencies for unfair advantage. This talk will examine both the theoretical underpinning and empirical evidence on currency intervention and manipulation, with the goal of better understanding when exchange rate stabilization is effective from the point of view of domestic policy-makers and when it should be considered manipulative from a global perspective.