When they decide which derivatives are considered swaps under the Dodd-Frank Act, U.S. regulators will unleash a cascade of rules on the $648 trillion global market designed to prevent a repeat of the 2008 credit crisis.

The Commodity Futures Trading Commission is poised to complete several hundred pages of regulations tomorrow that determine when trades by JPMorgan Chase & Co., Goldman Sachs Group Inc., Cargill Inc. and other companies must fall under rules to reduce risk and increase transparency. The Securities and Exchange Commission unanimously approved the rule July 6 without holding a public meeting.

“It's really very critical to complete the further definition of the word swap and the end-user exception,” CFTC Chairman Gary Gensler said in a telephone interview on July 5. “Those are foundational rules.”