Like current and future earnings prospects are the most important factors to consider when trying to forecast the long term direction of a stock, current and future interest rate prospects are the most important factors to consider when trying to forecast the long term direction of a currency. Because of this fact, currencies are highly sensitive to any economic news that can affect the country's interest rates, an important factor for traders of all time frames to understand.
As we learned in module 8 of our free basics of trading course located in the free course section of InformedTrades.com, when the central bank of a country raises interest rates this not only affects the short term rate that they target, but the interest rates for all types of debt instruments. If the central bank of a country raises interest rates then debt instruments of all types are going to become more attractive to investors, all else being equal. This not only means that foreign investors are more likely to invest in the debt of that country, but also that domestic investors are less likely to look outside the country for higher yield, creating more demand for the debt of that country and driving the value of the currency up, all else being equal.
Conversely, when a central bank lowers interest rates, then interest rates on all types of debt instruments for that country are going to be less attractive to investors, all else being equal. This not only means that both foreign and domestic investors are less likely to invest in the debt of that country, but that they are also more likely to pull money out to seek higher returns in other countries, creating less demand for, and a greater market supply of that currency, and driving its value down, all else being equal.
Once this is understood, it is next important to understand that foreign investors are exposed to not only the potential profit or loss from interest rate changes on the debt instrument they are investing in, but also to profits and losses which result from fluctuations in the value of that country's currency. This is an important concept to understand, as it generally will work to increase the profits for investors when interest rates increase, as the increase in the value of the currency is realized when they sell the investment and convert back into their home country's currency. This gives the foreign investor that much extra return on their investment, and that much extra incentive to invest when interest rates rise, driving the value of the currency up further all else being equal.
Conversely when interest rates decrease, there will be less demand for the debt instruments of a country not only because of the lower yield to investors, but also because of the decrease in the value of the currency that normally comes with a decrease in interest rates. The additional whammy of a loss to the foreign investor from the currency conversion that results as part of the investment, further incitivizes them to put their money elsewhere, decreasing the value of the currency further, all else being equal.