European market participants speculate on the possibilities of an interest rate change at these meetings. The ECB has a target rate for inflation, measured by the Harmonized Index of Consumer Prices (HICP), of 2%. Interest rates are changed to help maintain an inflation rate close to their target. As with interest rate speculation in other markets, if the ECB Announcement provides information different from the speculation, severe market impact is usually seen.
A general rule to keep in mind when interpreting central bank data such as that released in this announcement, is that higher interest rates are bearish for equity markets, while lower rates are bullish.