A Long butterfly consists of a "body" and "wings." A buyer of the wings purchases one unit each of two outside strikes and sells two units of the inside strikes, e.g. buys 100 March IBM 100 calls and 100 March IBM 110 calls, and sells 200 March IBM 105 calls. The buyer of the wings earn maximum profit if the underlying settles at the middle strike. The buyer of the wings' maximum loss is limited to the premium paid. The seller of the wings realizes maximum profit (equal to the premium received upfront) if the underlying settles outside of the range of the strikes (in our example, below 100 or above 110). The seller's maximum loss is capped at the value of the difference between the middle strike and the outside strike less premium received.