No animals were harmed in this financial experiment, but some human egos were bruised.

Burton Malkiel famously wrote in “A Random Walk Down Wall Street” that “a blindfolded monkey throwing darts at a newspaper’s financial pages could select a portfolio that would do just as well as one carefully selected by the experts.” A year ago the journalists at Heard on the Street decided to see if they could beat the crème de la crème—fund managers presenting their stock picks at the annual Sohn Conference in New York.

The...