An alternative in deriving subjective probabilities in the futures wagering market

Abstract

Implied subjective probabilities from futures wagering markets are typically determined using a system known as “fair odds.” Here, an alternative system of calculating subjective probabilities—“quasi-parimutuel”—is offered. Instead of considering individual lines independent of the remainder of the wagering opportunities, the quasi-parimutuel method considers the ratios of wagers required between lines such that a constant return is generated for every line. As a result, relative to the fair odds system, favorites (underdogs) have higher (lower) subjective probabilities, and expected returns across all wagers vary.