Samuel M. Hartzmark

Investors' perception of performance is biased because the relevant measure, returns, is rarely displayed. Major indices ignore dividends thereby underreporting market performance. Newspapers are more pessimistic on ex-dividend days, consistent with mistaking the index for returns. Market betas should track returns, but track prices more than dividends, creating predictable returns. Mutual funds receive inflows for “beating the S&P 500,” price index based on net asset value (also not a return). Investors extrapolate market indices, not returns, when forming annual performance expectations. Displaying returns by default would ameliorate these issues, which arise despite high attention and agreement on the appropriate measure.

Textbook finance theory assumes that investors strategically try to insure themselves against bad future states of the world when forming portfolios. This is a testable assumption, surveys are ideally suited to test it, and we develop a framework for doing so. Our framework combines survey experiments with field data to test this assumption as it pertains to any candidate risk factor. We study consumption growth to demonstrate the approach. While participants strategically respond to changes in the mean and volatility of stock returns when forming their portfolios, there is no evidence that investors view this canonical risk factor as relevant.

A contrast effect occurs when the value of a previously-observed signal inversely biases perception of the next signal. We present the first evidence that contrast effects can distort prices in sophisticated and liquid markets. Investors mistakenly perceive earnings news today as more impressive if yesterday’s earnings surprise was bad and less impressive if yesterday’s surprise was good. A unique advantage of our financial setting is that we can identify contrast effects as an error in perceptions rather than expectations. Finally, we show that our results cannot be explained by a key alternative explanation involving information transmission from previous earnings announcements.

Published: SAMUEL M. HARTZMARK & KELLY SHUE, 2018. "A Tough Act to Follow: Contrast Effects in Financial Markets," The Journal of Finance, vol 73(4), pages 1567-1613.