A stylized fact associated with inventory behavior is that the variance of production exceeds the variance of sales. This paper presents a model of production decisions with demand uncertainty that incorporates nonnegativity constraints on inventories. Even with no productivity shocks, optimal behavior by the firm is consistent with this stylized fact, either if demand exhibits positive serial correlation, or if the firm can backlog excess demand.

The countercyclical pattern of inventory-sales ratios is a striking feature of inventory behavior. In a model where inventories are productive for sales, both the markup of price over marginal cost and expected changes in marginal cost are key determinants of that ratio. This paper argues that costly variation in factor utilization gives rise to countercyclical markups in production-to-stock manufacturing industries. The markup turns out to be more important than intertemporal substitution in explaining the behavior of inventory-sales ratios.