That may sound extreme, but some scholars, such as the 2004 Nobel Prize winner Ed Prescott, have shown that, historically, holding a large diversified portfolio of stocks long enough is generally a far better investment than ultra-safe US Treasury bonds. A back-of-the-envelope calculation shows that with the risk premium removed, stocks prices could easily triple from existing levels, with price/dividend ratios soaring to over 200, compared to historical averages of 40 to 50.