摘要：Cotton is among the most internationally traded agricultural commodities. As a result, cotton prices are often described in terms of a world price. This world price, called the A Index, has been published by the trade group Cotlook since the mid-1960’s and is generally accepted as representative of a global price for cotton. As a world price, the A Index is derived as an average of export offers from cotton merchants for fiber delivered to Far Eastern ports, where most of the world’s cotton is spun into yarn. In addition to the average that is the A Index, Cotlook also publishes merchant offers for specific qualities of cotton from specific countries. Given that cotton prices were the most volatile of all agricultural commodity prices during the 2010/11 crop year, it could be expected that historic relationships among prices for different qualities and growths may have changed. This research is designed to identify and describe these changes. Cointegration analysis examines relationships between prices according to quality and country of origin and description of how were affected by recent volatility with the objective of informing discussion of potential implications for global cotton trade.
