This paper examines how to properly specify and test for factors that affect the exchange-rate exposure of stock returns. We develop a theoretical model, which explicitly identifies three channels of exposure. An industry's exposure increases (1) by greater competitiveness in the market where its final output is sold, (2) the interaction of greater compeitiveness in its export market and a larger share of exports in production and, (3) the interaction of less competitiveness in its imported input market and the smaller the share of imports in production. Using a sample of 82 U.S. manufacturing industries at the 4-digit SIC level, classified in 18 2-digit industry groups, between 1979 and 1995, we estimate exchange-rate exposure as suggested by our model. We find that 4 out of 18 industry groups are significantly exposed to exchange-rate movements through at least one channel of exposure. On average, a 1 percent appreciation of the dollar decreases the return of the average industry by 0.13 percent. Consistent with our model's predictions, as an industry's markups fall (rise), its exchange-rate exposure increases (decreases).