These are usually prescribed by the exchange as a percentage of the total value of the derivative contracts. (kotaksecurities.com)
One of the nettlesome provisions would regulate leverage based on the gross notional value of derivative positions. (mutualfundobserver.com)
While there's no way of knowing for sure, estimates of the face value of all derivatives outstanding tops a quadrillion (1,000 trillion) dollars, or more than 14 times the entire world's annual GDP. (business.time.com)