In Eq. (1), b2i represents the exchange-rate exposure. Similar to a market beta,
the exchange-rate exposure measures the percentage change in the rate of return on
a firm’s common stock against a 1% change in the exchange rate. Because we are
interested in examining the relation between exchange-rate exposure and currency
derivative use, we use J.P. Morgan’s ‘narrow,’ trade-weighted, nominal exchangerate
index, which measures the strength of the dollar relative to a basket of 18 other
OECD currencies.6 We choose this index because firms are more likely to use deriva-tives in these currencies and derivatives are generally hedges against nominal
exposure. However, we also examine the sensitivity of our results by using a real,
much broader index (RX-101) published by the Federal Reserve Bank of Dallas,
which measures the strength of the dollar against 101 of the US’s trading partners.
Finally, to control for the market movements, we use the CRSP monthly value weighted
market index.