Market Cycle
  
See: Business Cycle.
Market cycles go up and down like waves. And there are storms. The market for insurance goes up and down. People get nervous. Then less nervous. So they buy more. Then they buy less.
Markets go through cycles like this "naturally." The biggest market cycle is that of the stock market, which goes through a big market cycle about every eight years. Why every eight? Eh, nobody's really sure, but in part, the oscillations are driven by changes in rates from The Fed and other presidential cycle-y things.