[JURIST] Wall Street organizations International Swaps and Derivatives Association (ISDA) and Securities Industry and Financial Markets Association (SIFMA) [official websites] on Friday filed a lawsuit challenging a regulation [complaint, text] implemented by the Commodity Futures Trading Commission (CFTC) [official website] that limits speculative trading. The CFTC adopted a Position Limits Rule on October 18 on the grounds that the rule was authorized by the Commodities Exchange Act [CFTC backgrounder], and published the rule in the Federal Register. The regulation restricts…