A number of responses here are inaccurate. Reg-T margin is not risk based. One option can provide an offset to another option but only if your clearing broker pairs them off. They all use some type of option optimizer that pairs off long and short options in a systematic manner. It does not mean the max loss of all your options in one symbol will be your requirement. Your requirement can be much higher. If you want risk based margin, you need to qualify for a portfolio margin account (PMA). The volatility of the option does not change the reg-t margin requirement unless your clearing broker uses another process for certain symbols. With a PMA, the requirement from the OCC is based on shocking all the options and equities in one symbol or group type by a certain percentage. E.G. For equites like AAPL, the shock is 15%. They take all the AAPL option together and calculate the worst loss from +/-15% and that is the margin requirement for your AAPL positions from the OCC. Your clearing broker can always require more, but not less. If AAPL vol increases and decrease, it would be part of the expected loss from the stock movement of 15%. Bob