The impact of delta on a short call butterfly option trading strategy is that a change in the underlying asset's price will affect the value of the options in the position differently. The call options that are sold (short) will have a negative delta, meaning that as the underlying asset's price increases, the value of the short call options will decrease. The call options that are bought (long) will have a positive delta, meaning that as the underlying asset's price increases, the value of the long call options will increase. This creates a butterfly shape in the position's delta profile. If the underlying price is lowest strike price in a short call butterfly, then the net delta is slightly negative. If the is trading above the highest strike price, then the net delta is slightly positive. Overall, a Short Call Option Butterfly profits from a stock price rise above the highest strike price or a fall below the lowest strike price.