Imagine somebody who discovered secondary-school maths tough being grilled about logarithms. That’s how loads of fairness traders look in case you ask them about foreign money danger. It’s not as a result of the query is novel: any shopper can spot that the share worth of an abroad firm, or one doing enterprise throughout borders, should rely on foreign-exchange (FX) charges. It’s as a result of it’s simple to pose, however maddeningly exhausting to reply. Forecasting earnings is already a ache. It turns into a lot worse when the duty is to make forecasts for every firm in a portfolio, earlier than splitting prices and revenues by maybe a dozen currencies, after which netting all of it off towards hedging preparations made years in the past by a now-retired treasurer. Unsurprisingly, such evaluation is usually dumped within the “too exhausting” bucket.