Any advisor can tell you that while Modern Portfolio Theory (MPT) has a lot of strengths, it also has many shortcomings as it relates to investor psychology. For instance, Modern Portfolio Theory asserts that multiple aims can be achieved within the same portfolio, but this does not mesh well with how investors think about money—where each account has its own life purpose. Secondly, risk is an area of major disconnect. Portfolio Theory looks at risk in terms of historical standard deviations of volatility, whereas humans think of risk in more life-relevant terms: what I my portfolio does earn enough to pay for my child’s tuition? This is where goals-based investing comes in, as it focuses on how portfolios can be constructed—and reported on—in such a way as to match investor psychology about the life goals they are trying to achieve.
FINSUM: MPT has been revolutionary for quantifying risk and return profiles, but for many it simply does not resonate on the “human” level needed for some advisors to motivate and connect with their clients.