Wikipedia
iPredict is a New Zealand prediction market that offers prediction exchanges on current events, political issues and economic issues. iPredict is jointly owned by the New Zealand Institute for the Study of Competition and Regulation and Victoria University of Wellington. The site launched on 9 September 2008.
iPredict's system is a prediction market which allows members to trade contracts (take 'positions') on whether future events will or will not occur. The contracts have judgement criteria which define how they will be settled. For example, a contract could be called "There will be a National Prime Minister after the next General Election". Other events include financial predictions, such as "The NZX50 Gross Index closes equal or higher on Friday 7 December, than the closing price on Thursday 6 December." iPredict facilitates trades between members, but does not participate in trading itself.
Traders can either buy (go long on) contracts, indicating that the event will happen or sell (go short on) contracts, indicating the event will not happen. The trading unit is a contract with a settlement value, typically either $0 or $1 and the contract can trade between these values where 1 percent equals $0.01 in value. If the event specified in a given contract occurs, the contract settles at 100 percent or $1; otherwise, the contract settles at 0 or $0 in value. Thus, the current price of the contract can be imputed as the market's global opinion of the probability that the specified event will occur. Traders can trade both before and during an event. iPredict often has a market maker to provide a two way price at almost all times.