The whole concept of trading being "a zero sum game" is completely false and dangerous. Is buying insurance on a house a "zero sum game"? Is a cattle auction just a form of gambling for farmers. Is it a strange co-relation that countries with the highest futures and stock volumes also have the highest GDP? By assuming a risk for someone you remove and obstacle to doing business. When I sell a future on ZF (five year US government bond) a bank is able to hedge it's interest rate risk so it can lend out more money. And that is not the only economic benefit from trading. There are thousands of subtle benefits. In fact I think trading is one of the most noble occupations as we move into a post industrial economy.