Hans R. Stoll, Commodity Futures and Spot Price Determination and Hedging in Capital Market Equilibrium, The Journal of Financial and Quantitative Analysis, Vol. 14, No. 4, Proceedings of 14th Annual Conference of the Western Finance Association, June 21-23, 1979 (Nov., 1979), pp. 873-894

1. This paper presents and tests a model of dealer inventory response. The estimated inventory responsiveness coefficient is statistically significant and its magnitude is consistent with reasonable values of underlying variables which, it is hypothesized, determine the coefficient.2. The sign of the inventory responsiveness coefficient indicates that dealers tend to be passive and acquire shares when prices fall and sell shares when prices rise. This type of behavior is sometimes termed “stabilizing.”3. Dealer inventories tend to increase on days prior to price declines and tend to decrease on days prior to price increases; that is, inventory changes tend to be “destabilizing” with respect to future price changes. This implies that a fraction of the public trades on superior information and that dealers tend to lose money to such information traders.4. There is a strong tendency for dealer inventory levels to return to normal, presumably zero. The implied typical inventory holding period is about 8 to 10 trading days.5. Comparison of NASDAQ dealers and NYSE specialists shows that the pattern of inventory responsiveness is very much the same for the two. This suggests that both act in accordance with the underlying economic model and that differential regulation has little effect on typical inventory responsiveness.6. This finding does not obviate the possibility that individual dealers or specialists behave in atypical or undersirable ways, and that the extent of such atypical behavior might depend on the degree of public regulation of dealer activities. An exhaustive comparative study of deviations from normal behavior was not possible. However, it was possible to compare the frequency of nonstabilizing transactions in which price change and inventory change on a given day are in the same, rather than opposite, direction. One could not conclude that NASDAQ dealers had more nonstabilizing activity than NYSE specialists.

The sources of trading friction are studied, and simple, robust empirical measures of friction are provided. Seven distinct measures of trading friction are computed from transactions data for 1,706 NYSE/AMSE stocks and 2,184 Nasdaq stocks. The measures provide insights into the magnitude of trading costs, the importance of informational versus real frictions, and the role of market structure. The degree to which the various measures are associated with each other and with trading characteristics of stocks is examined.

The relation between the square of the quoted bid‐ask spread and two serial covariances—the serial covariance of transaction returns and the serial covariance of quoted returns—is modeled as a function of the probability of a price reversal, π , and the magnitude of a price change, ∂, where ∂ is stated as a fraction of the quoted spread. Different models of the spread are contrasted in terms of the parameters, π and ∂. Using data on the transaction prices and price quotations for NASDAQ/NMS stocks, π and ∂ are estimated and the relative importance of the components of the quoted spread—adverse information costs, order processing costs, and inventory holding costs—is determined.

The relation between the square of the quoted bid-ask spread and two serial covariances—the serial covariance of transaction returns and the serial covariance of quoted returns—is modeled as a function of the probability of a price reversal, π, and the magnitude of a price change, ∂, where ∂ is stated as a fraction of the quoted spread. Different models of the spread are contrasted in terms of the parameters, π and ∂. Using data on the transaction prices and price quotations for NASDAQ/NMS stocks, π and ∂ are estimated and the relative importance of the components of the quoted spread—adverse information costs, order processing costs, and inventory holding costs—is determined.