Bull & Bear Markets
Though investment markets are unpredictable, they tend to move in cycles of ups and downs. A bull market occurs when stock prices as a whole move upward for a prolonged period. Bull markets do not last a specific amount of time, nor is there a definite length of time that passes between them. The rate at which stock prices rise during different bull markets also varies widely.
Bear markets happen during periods of falling stock prices, and are generally said to occur when prices fall at least 20% from the most recent high. Bear markets in stocks tend to occur when investors sell off shares in anticipation of worsening market conditions and falling corporate profits. In the bond market, they usually result from rising interest rates, which tend to motivate bondholders to sell their older bonds for new issues with higher rates.