The equity and bond markets have been relatively stable with a negative correlation for the past three decades. However, that may be about to change, according to the Financial Advisor in "Forget 30 Years Of Stock And Bond Divergence, Bernstein Says."
If this shift does occur, trustees will need to pay attention. Trustees are generally required to invest trust assets by following the prudent investor rule. For the last 30 years, that has meant following the modern portfolio theory and diversifying assets between different classes of investment. However, a return to bonds and equities having a positive relationship, will make diversification of investments more difficult, and Trustees' jobs will become much more difficult.
Of course, this shift has not happened yet and might never happen. Most market predictions never come to fruition. However, trustees should pay attention and make sure that they are following the best advice about investing trust assets.
Reference: Wealth Management (Jan. 10, 2017) "Forget 30 Years Of Stock And Bond Divergence, Bernstein Says."