contango = when the price of a futures contract trades above the spot price. if the difference is maintained till expiration, then you have overpaid for the contract and thus realized a loss. the flipside is backwardation, which means the spot price trades above the price of the futures contract, which equals a profit. in UVXY's case, it trades based on the shorterm futures of the VIX with a 2x lever. so whatever the difference is (contango or backwardation), you multiply it by 2 to get the trading value of UVXY. since the VIX spot is currently trading well below the shorterm futures, if this were to be maintainted till expiration, the difference in contango would be realized as a 2x loss for the ETF. however, this could just as easily change into a case of backwardation if the VIX were to spike above the shorterm futures prices. so in reality, all this talk about contango or backwardation is moot, unless you plan to hold UVXY for an extended period of time, which isn't advisable anyways. this shouldn't be held for more than 30 days.