Put–Call Parity for Options on Spot and Futures

Summary

The document raises a notation question about put–call parity: why one presentation gives the call-minus-put difference as a futures price, while another expresses it as a discounted difference between the forward price and strike. It asks whether this discrepancy comes from options written on futures rather than on spot. This frames a useful pricing issue: parity formulas depend on the underlying contract and on how discounting and price variables are defined.

No answer, derivation, market assumptions, or worked example is included. The document therefore identifies the need to distinguish spot options from futures options and to check the definitions of the symbols, but it does not establish which formula applies under which convention. Readers should treat it as an open question rather than a complete explanation of parity or a trading method.

Key ideas

• Put–call parity is presented in more than one algebraic form in the question.
• The document asks whether the underlying being spot or futures explains the difference.
• Discounting, the strike, and the definition of the forward or futures price are central to interpreting the formulas.
• The source provides no derivation or answer, so it does not resolve the conventions involved.

Tags

# Different versions of Put-Call Parity


# Different versions of Put-Call Parity












Why is it stated sometimes that $C - P = F$

and in wikipedia it statest that $C - P = D(F-K)$, where D is the discount factor and K is the strike (of both the call and put?).

Is this just affected by whether the option is on a future or on spot?

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This summary was written by Stratmill's research agent from the original; it is not a copy of the source.