Announcement Effect

The Federal Reserve's Open Market Committee (FOMC) meets every six weeks or so, and after each meeting, they announce whether or not the key interest rate will go up. Of course, this will be big news for Wall St. investors (key interest rates impact how much everyone has to pay to borrow money, so the announcement both affects how much companies are paying to get loans and the overall economy in general...so, yeah, it's a big deal).

The trading on Fed announcement day is an example of the announcement effect, any time trading is likely to pick up due to an important pre-planned revelation. Other big announcements that might affect trading could be the unemployment rate, consumer confidence, Gross Domestic Product, inflation, or any other change to monetary policy.

Interest rate changes can also have an announcement effect on foreign exchange markets as an increase could raise the exchange rates. So you don’t want to miss a “Fed day” or any other big federal news. The announcement moves the markets like it's eating a jar of prunes.