Active funds generally underperform during periods of economic growth and we're in the longest running bull market of all time right now. Ackman makes mistakes

Active funds generally underperform during periods of economic growth and we're in the longest running bull market of all time right now. Ackman makes mistakes but he is still very insightful and backs his opinions with dollars. No one who deals with risk is going to have a perfect track record, and even though his Valeant and Herbalife bets didn't pay off the opportunities/flaws he saw were real, other factors just happened to be more important such as Icahn propping up the price of Herbalife and Valeant's accounting problems.