sentences:  Since this position is short vega when the underlying is above the upper strike price, this dynamic is again helpful to the equity options trader.For equity markets (as described above), the call backspread does not generally offer these helpful dynamics because the generally associated changes in volatility as price moves in the equity markets may exacerbate losses on a bearish move and reduce profits on a bullish move in the underlying.With options on commodity futures (and possibly inverse ETFs), this relationship may be reversed as the observed correlation between price movement and implied volatility is positive meaning that as prices rise, so does volatility.