DMO - I'm shocked? Hardly. This is all getting a bit convoluted. First, my bad for using a 1.5% interest rate in a hypothetical example. The point of that was to present an example with a difference in cost. Obviously, if the interest rate is zero, there's no carry cost and ATM puts and calls will have identical values and question resolved 3 pages ago. The purpose of the hypothetical was to resolve my question as to whether a syntthetic straddle with puts and stock was a better choice than puts and calls or stock and calls. In re MY interest rate, that is the problem but AFAIK, I don't see your answer as the solution. Modeling with my interest rate of near zero will put me in a parallel universe vis a vis the market I think Donnap resolved it with the answer that "We both know that the avg. retail doesn't earn int on short proceeds and for now we pay - but the option pricing assumes that we are all MMs." IOW, if the options have an imbedded carry cost due to some interest rate (pick your own number) but my broker screws me by not paying me less than fair interest on the cash balance then I don't make up any difference due to carry cost in the options that I'm buying. And therefore my conclusion is that the puts/stock position is the best chioice when considering only carry cost, in isolation (ignoring margin, availability, etc.).