From the Wall Street Journal:
The amount of cotton held in hamlets throughout China is unknown, but, with 25 million cotton farmers, a Chinese cotton agency estimates it could amount to about 9% of the world's cotton supply. And the situation is occurring throughout the supply chain. Many ginners and merchants in China are keeping warehouses full, according to the agency, in an attempt to obtain higher prices.
Expectations that prices will rise are driving the apparent stockpiling, which causes short-term shortages and leads prices to rise further. The situation is complicating an already volatile picture for cotton, which has jumped to 140-year highs in the U.S. and has become a symbol of brewing commodity inflation around the globe.