A strategic use of asset allocation can help limit systematic risk. For example, in the bond market, when interest rates rise, the value of previously issued bonds decreases, thereby decreasing their relative value compared with bonds currently selling in the market. When this happens, new investors will be attracted to the bond market because of the higher rates. However, the popularity of the bond market has a negative effect on the stockmarket because investors will tend to leave stocks for bonds, where they can get a higher return with lower risk.
When the opposite happens, as it inevitably does, and interest rates drop, investors tend to put money into stocks for their higher potential returns, driving stock prices up.