If all of the other inputs into black scholes (divs/rates/time to maturity/strick/current price/etc) are all the same between two pairs of calls/put contracts on the same security, shouldn't the implied volatility be the same?
For example I see SPY and AAPL has having similar IV for ATM put and calls.
However, it seems like for NFLX and GME, the calls have slightly higher IV? Why is that? In some cases, I have seen the ATM puts command a higher premium (embedded financing cost of shorts, but why is the IV sometimes lower for those puts?)