aka the father of modern portfolio theory

“Perhaps the most important job of a financial advisor is to get their clients in the right place on the efficient frontier in their portfolios,” he told me. “But their No. 2 job, a very close second, is to create portfolios that their clients are comfortable with. Advisors can create the best portfolios in the world, but they won’t really matter if the clients don’t stay in them.”

In other words, MPT and behavioral economics have to work together. And Moskowitz figured that out early…

“There was a big difference in my views about how and why to use mean variance analysis (that’s academic-speak for MPT) in my 1952 paper and in my ’59 paper. In the ’52 paper the only portfolio constraints I was concerned about were to avoid negative returns. But by 1959, I was concerned about [how investors would react to] the portfolio construction: For the comfort of the clients, we put constraints on ‘risky sounding stuff,’ such as junk bonds, etc. We knew that might dampen returns, but it was better than if they chicken out in a down market.”

From an interview with Bob Clark.