what is a zero sum game 
zero sum is a situation often cited in game theory in which one person s gain is equivalent to another s loss so the net change in wealth or benefit is zero a zero sum game may have as few as two players or as many as millions of participants in financial markets options and futures are examples of zero sum games excluding transaction costs for every person who gains on a contract there is a counter party who loses investopedia laura porterunderstanding zero sum gameszero sum games are found in many contexts poker and gambling are popular examples of zero sum games since the sum of the amounts won by some players equals the combined losses of the others games like chess and tennis where there is one winner and one loser are also zero sum games derivatives trades are also often cited as zero sum games since every dollar earned has to be lost by another party to the transaction zero sum vs positive sum gameszero sum games are the opposite of win win situations such as a trade agreement that significantly increases trade between two nations or lose lose situations like war for instance in real life however things are not always so obvious and gains and losses are often difficult to quantify 