Thank you. In fact I'm well aware of the options-specific functions. However, the topic of "artifical" (=combined) assets is not covered. In fact it is not an options-specific topic as such, it just happens to be quite important in the context of options trading. Also the options-related articles on FH are not helping in this direction as the topic of combined positions is not touched (or only very rudimentary in the way the margin is calculated).