Basic finance theory says that investors can get the best balance of risk and reward by owning pieces of as many of the world ' s asset classes as they can , from stocks to gold , alpacas to saffron . for years , the s and p 500 - stock index of the biggest u . s . companies was the best approximation of that ideal available to investors and they flocked to it . but in the past decade , the world ' s financial markets have changed in unexpected ways 對于這些大公司的藍籌股一直勢態低迷的情況,文章從歷史分析入手,通過90年代后期藍籌股的異常牛市來解釋當期一蹶不振的原因:一方面是隨著20世紀末市場化全球化的進程,經濟發展的大爆發,藍籌股指數達到一個過高的頂點,之后很難再超過另一方面是經濟過熱之后的適當緊縮,以及911等事件對美國經濟的打擊,藍籌相對于小企業股票的應變性差的問題。