Quote from clarodina:
for synthetic long isn't this going to take double of spread because of two options position closing? one position spread is 3 cents two position would double. how is this approach be superior than using buying 2 calls at delta 0.5?
volatility and theta affects the price movement. how to adjust using the geeks ratios so the price movement would be same with the stk price movement? like delta 0.5 the adjustment would be double the position to get the same price movement
generally how much would the real delta change in option value be different than the theoritical one?
I can't parse your first two sentences. Whether a synthetic long is superior to buying two calls depends on what your goal is. If you want a pure leveraged, delta 1, theta = vega = gamma = 0 directional play a synthetic long does the trick. But it works both ways -- if the underlying drops 5 bucks each call/put combination loses $500. Just like for a future, you need margin and the worst case losses are horrid. Buying only calls limits your losses but you are still stuck with dealing with volatility and time decay. Now I suppose you could try to maintain an approximate delta 1 position with calls only by buying 2 ATM calls per 100 shares of stock and then selling them off as the stock rises and buying more as it lowers. (Sort of the opposite of basic vanilla dynamic hedging of options, where you buy and sell stock to match the delta of the options.) But you'd have no control over theta and vega. It sounds to me like its more trouble than it's worth. If you want to make directional plays with options and want to keep your losses bounded, just accept the fact that delta isn't going to be constant.