I could have started a new thread , but was not sure if this sort of question was asked on the elite boards ... which futures contract has the most leverage per margin? maybe spot fx is the most highly leveraged derivative out there based on the leverage 200 : 1 ? or is 200:1 a thing of the past ? ( I know ... should read all the posts on elite and not have to ask these sort of questions )
the question is what are you measuring: is it margin versus underlying or probably more interesting margin versus average ticks multiplied by the value of the tick. If you are looking for the first one, i think it should be one of the short term intrest rates contracts.