Measuring Gaps Between Hypothetical Investment Returns and Actual Investor Returns

Abstract

Actual investor returns from mutual funds lag behind hypothetical returns based on a fixed initial investment and reinvestment of all distributions. This gap arises from behaviorally driven errors in timing. The nonproprietary literature on this performance gap has emphasized the relationship of this gap to overall returns on stocks and mutual funds. This article seeks to address more directly the relationship of behaviorally driven gaps in investment returns to downside risk, upside gain, and overall volatility. Documenting the existence of this gap across the universe of publicly traded securities — not only in the aggregate, but also on a security-by-security basis — may provide a legal basis for requiring mutual fund and exchange-traded fund managers to compute and disclose that gap.