Rational Expectations and Volatility in Foreign Exchange Markets

The theory of rational expectations is one of the biggest influences on macroeconomics today. Rational expectations state that individuals and markets incorporate all the available information when they make forecasts (predictions) about the future based on their expectations. An important part of the rationale for why exchange rates move the way they do in the foreign exchange market is due to traders taking into account how actual event results compare with forecasts prior to the announcement.

Exchange rates are inherently forward-looking; that is, when investors evaluate the quality of a currency, they consider both present conditions and expectations of future inflation, interest rates, and economic growth. As soon as new information arrives (with regard to economic conditions), those expectations are modified or updated. This makes the timing and content of the arrival of information into the currency markets critical.

The critical concept is the forecast error, which is the difference between the actual result and the expected result. Analysts create consensus forecasts before major economic announcements (e.g., inflation reports, employment numbers) are reported. Consistency (i.e., actual result vs. consensus forecast) results in little movement of exchange rates, while inconsistency (i.e., actual result vs. consensus forecast) causes unexpected shifts in exchange rates to occur.

Economic forces cause behaviour that is based on market information processing. In a rational expectations paradigm, many anticipated policy shifts before that policy shift occurs have already been established in prices. For example, if a central bank gives its indication that rates will most likely go up, market actors will have already made the necessary adjustments before the rate increase itself occurs. Indeed, once the rate increase occurs, it will have already been factored into the price of the currency. In general it is when an actual policy action occurs that is different from market expectations – i.e., when there is an unanticipated policy shift – that there will be much greater market reaction.

There are numerous examples that illustrate this point. The United States Consumer Price Index (CPI) is one global markets' most watched macroeconomic data releases. The release of June 2022 CPI showed inflation rising substantially more than what had been expected, and the immediacy with which the U.S. Dollar appreciated during that period reflected a sharp change in what had previously been expected for future interest rates by the Federal Reserve. Likewise, when U.S. Non-farm Payroll report information is released and shows an unexpected change (versus prior expectations), the immediate change in financial markets has traditionally been drastic and caused a spike in volatility within currency pairs (i.e., EUR/USD; USD/JPY) and other financial instruments as a result of traders hurriedly reassessing their expectations regarding future monetary policy and overall economic strength.

Research data from financial markets illustrate this phenomenon very well. A majority of the daily fluctuations in currency prices occur within minutes of the release of significant macroeconomic information. Often there is a spike in trading activity during this time, as well as an increase in bid/ask spreads from their normal levels to deal with new trader interests in either side of an exchange. The existence of clusters of price fluctuations associated with economic data releases underscores that it is expectations which drives the markets rather than actual levels of any given currency.

Traders benefit from having multiple options (currency pairs) to react to shifts in their expectations of the marketplace. For example, in forex trading with FxPro, there are a variety of different choices available to you that will allow you to have an opinion about how well the economy of a specific country is doing relative to another. An investor may feel that the United States has greater GDP than the market anticipated when compared to the countries in Europe and may take action by buying or selling in USD/EUR (or similar) pairs. Each of these pairs provides valuable information about global interdependence (or interrelation) for each participating economy.

Central bank "forward guidance" is another factor that is critical for traders; it is a way for central banks to communicate their future plans for monetary policy. By providing future monetary policy guidance, central banks allow the marketplace to adjust to these expectations prior to the actual announcement being made, which creates greater certainty in some cases. At the same time, when there is a disparity between what is reported and what actually occurs, an increase in market volatility may happen from forward guidance. Central banks often lead the marketplace and once information is stated to be accurate becomes incorrect, the marketplace often has to quickly re-evaluate its previous expectation.

Expectations refer to beliefs about future economic events, typically based on a rational assessment of past data. Rational expectations can recall anything in the actual universe, as long as rational considerations play a part in that setting. This makes rational expectations highly applicable to forecasting exchange rates over time. Still, this is not the end of the discussion; firms must be aware of the implications on company operations and related actions, as well as any potential ramifications for company reputation.