Designates a market place for options on the result of a play. Does the event occur, is the option 10 euros value. In contrast to bets with fixed ratios here fans and experts tap against each other, so that the course over supply and demand is fixed. Besides the option in the full-coming market can be sold to the market price. The price of the option varies, for example depending upon momentarily result. Sport stock exchanges offer usually better ratios as classical bookmakers, whereby this partial becomes balanced over the service fee for the trade of the options. The interesting at sport stock exchanges is the possibility to go short, i.e. the current sales of an option, which is redeemed at a later time. Here profits as well as losses can be substantially increased so that this will turn out but this option is only for experts. In addition each individual user can function as bookmaker with individual sport stock exchanges, to place and own bets. Here is however the important to select a stock exchange which achieved critical minimum of users, around an interaction from supply and demand to make possible