Diversification Is Dead, Long Live Diversification!
指出受托人应为主动管理者使用更好的基准，建议在基准集中时降低跟踪误差、分散时提高跟踪误差，并质疑标普500指数近年是否失去了分散化效率。
Fiduciaries should use better benchmarks for skilled active managers. If using a capitalization-weighted benchmark, they should allow dynamic tracking: lower tracking when the benchmark is concentrated and higher tracking when it is diversified. The components of “active management” are domain experience, data extraction, and digital excellence. The goal of a systematically quantitative process is to “outperform” by creating an expert system. If successful, the process adds value in excess of an alternative. The dominant <italic>alternative</italic> (benchmark) that has survived and thrived is a cap-weighted index of 500 traded stocks created by Standard & Poor’s in 1957. However, the S&P 500 Index as a portfolio has in recent years lost much of the benchmark-essential requirement—efficiency in diversification. Is the well-known Mark Twain quote relevant when applied to index diversification: “The reports of my death are greatly exaggerated”?