Exchange rate differences arise for anyone holding assets or liabilities in foreign currency. For an investor, this is part of the result unrelated to the instrument itself: a currency deposit may generate income at a given rate, but if the foreign currency strengthens, the result in national currency may be less than expected.
In company reports, exchange rate differences are reflected separately and can significantly distort profit dynamics. An exporter with foreign currency revenue and a company with foreign currency debt will show opposite results from the same exchange rate movement, even though their operating activities remain unchanged.
This leads to an analysis rule: when an issuer's profit changes sharply, check whether it is explained by revaluation of foreign currency items. Such profit or loss does not reflect business quality and typically does not repeat.
A distinction is made between realized differences, arising from actual exchange or debt repayment, and unrealized differences—the result of revaluation at the reporting date. The latter exists only on paper and may reverse.