The evolution of the market. Although US firms operate below their production capacity, the market remained surplus. Thus, between 1988 and 1993/94, world exports increased from 46.8 to 28 million tons, followed by a fall in prices of 8%. The evolution of stocks in the USA shows the regulatory role they have played so that the situation can not get worse: the overall volume of stocks first rose from 9.3 in 1988 to 12.6 million tonnes in 1992, before falling back to 9.2 in 1993. The increase in inventories made it possible
to lower prices, thus favoring the recovery of demand. World trade thus rose from 26 million tonnes in 1993 to 29.1 million tonnes in 1994 and steadily increased to 31 million tonnes in 1998, a 19% increase compared with 18% for production. There is a faster growth in demand relative to supply. However, the growth and modernization of production capacity is coming up against a demand that is becoming rather sluggish. Falling demand in Europe was offset by additional demand from Asia. This results in an increase in the demand for phosphoric acid, hence crude phosphate, and consequently a price which will reach the level of $ 44 per metric ton in 2000. The evolution of crude phosphate prices is explained by the ratio of production to world consumption of the product. It is also a function of the world demand for phosphate fertilizers obtained by successive transformations of the ore. In addition, it depends on the strategies of the actors, strategies of cooperation and conflict. The first strategic behavior concerns the agreement first observed between the US and France in the early 1960s, then between the US and Morocco for the stabilization of prices. The second type of strategic behavior, that of conflict, relates to the crisis of 1973 triggered by Morocco. It also concerns the period before the crisis with the collapse of prices due to the practice of rebates and discounts made by firms. For the overall market dynamics, the ratio of production to consumption on the price is measured by the stock. The change in the stock is therefore the explanatory variable for price movements. In addition, fertilizer consumption can approach the demand for crude phosphate. The fertilizer market generally provides useful information for assessing the interdependent effects of the phosphate market.