Factors affecting international equity returns To construct an efficiently diversified intemational portfolio of stocks, one must estimate the expected retum and the variance ofreturns for each security in the investment set plus the pairwise correlation structure. it may be easier to accurately estimate these parameters if a common set of factors affect equity retums. Some likely candidates are: macroeconomic variables that influence the overall economic environment in which the firm issuing the security conducts its business; exchange rate changes between the currency ofthe country issuing the stock and the currency of other countries where suppliers, customers, and investors of the finn reside; and the industrial structure of the country in which the firm operates.