Hi, I was just looking at SPY which was trading at 124.5 +-. If I go up 3.5 to do a 128/133 bear call spread, it prices at roughly 1.10 less .14 for a credit of .96. If I go down 3.5 to do a 121/116 bull put spread, it prices at roughly 1.69 less .78 for a credit of .91. A 120/115 bp spread prices at 1.51 less .67 for a credit of .84. I was just wondering where the differential comes from between a call and put in this situation with the put credit spread being less? It almost seems like there is a bias but since the etf is going down today, I would think that the price of put spreads should be increasing. Thanks for any clarification.