Larry, show me how the 50SMA is not a useful trading tool in the attached chart: <A HREF="http://stockcharts.com/def/servlet/SC.web?c=$SPX,uu[f,a]dacayyay[d19910401,19940801][pb50!i!d20,2!f]..." target="_new">http://stockcharts.com/def/servlet/SC.web?c=$SPX,uu[f,a]dacayyay[d19910401,19940801][pb50!i!d20,2!f]...</A>. I believe the better system is Bollinger Bands. When price crosses the middle BB, it hunts for the opposite BB. Simple, yet effective. Note the lower BB on the SPX is around 976 right now. Maybe that's why the 50SMA was crossed.