The Bremen Cotton Exchange is the guardian of the trading rules. The Bremen Rules have applied to the German cotton trade since 1872. They apply to all domestic and foreign cotton trading contracts.
Download: Terms Trading Rules
The Bremen Cotton Exchange determines the value differences in cooperation with the International Cotton Association, Liverpool. They are updated at irregular intervals.
The value differences for the respective standards record the price gradations for different grades and other quality characteristics. This includes, for example, the type of ginning for some qualities (rollerginned vs. sawginned).