当跌势加速，市场恐慌加剧，所有股票都会下跌，疯涨的个股无论基本面好坏，最后都会大掉
for example, On July 2, 2008
coal: wlt anr pcx jrcc mee.... all drop more than 15% in a day
steel: x schn zeus clf nue dropped more than 12%, rtp dropped 70 points
in 2 days
even oil price keep going up, many oil stocks dropped a lot such as apa
gmxr gdp pdo mxc wll.....
in a down trend, weak stocks get even weaker. no bottom, such as cme ice nyx,
solar: yge solf sol ldk tsl stp spwr jaso csun; tech: sndk nvda sigm leap...
trading strategy;
short or buy over bought stock's put when mkt begain panic(usually it happened after index dropped 2 or 3 weeks), keep shorting weak stocks until index reverse
