Currency markets have witnessed a sharp increase in government intervention since 1985. Many observers believe that this intervention promoted the dollar's depreciation between 1985 and early 1987, and that intervention has since helped to stabilize dollar exchange rates. This paper tests for a systematic effect of daily dollar intervention on exchange rate risk premia. We test for both portfolio balance effects and signaling influences by using daily data on central bank intervention (in dollars) against both the yen and the West German mark. Following work by Dominguez (1989) and Loopesko (1984), we measure the daily risk premium in terms of the deviation from uncovered interest parity. However, we follow other empirical analyses of exchange rates and allow for generalized conditional autoregressive heteroscedasticity (GARCH). Some evidence is found for both the portfolio balance and signaling channels.