This paper investigates the movement of manufacturing inventories and production over the business cycle to arrive at an asymmetric structural equilibrium-correction model. Initially cross-correlation coefficients and deepness and steepness tests for skewness are utilized to present descriptive statistics of the time series. Cointegration analysis is performed on each disaggregate inventory by stage of production (finished goods, work in progress and raw materials) with a set of explantory variables. Restricted cointegration vectors are added to the symmetric and non-symmetric specifications of the structural equilibrium-correction model. These are compared by parameter constancy tests and one-step ahead forecasts.