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Pricing an Asian Call with an Average Fixed at an Earlier Date

Article Quant Q&A · Author: user107224

Summary

The document considers a call payoff based on the terminal underlying price minus the average price observed over an earlier period ending at time τ. This is described as an Asian strike call, with the averaging window allowed to end before the option expires. The average need not span the entire life of the option.

Before the averaging period ends, the average is still changing, so valuation must account for the path-dependent strike in addition to the terminal payoff. Once that period has ended, the average is known at time τ; from then on, the claim can be treated like a European call with that realized average as its strike. The discussion does not provide a closed-form solution, numerical method, or detailed treatment of varying rates and volatility, so it offers a useful classification and timing distinction rather than a full pricing recipe.

Key ideas

  • The payoff is an Asian strike call whose averaging window ends at τ.
  • The averaging window does not have to extend to the option's maturity.
  • Before τ, the strike remains path-dependent because the average is still being formed.
  • After τ, the realized average is known and acts as the call's fixed strike.

Tags

Full text
# Pricing of Asian-like option


# Pricing of Asian-like option












I am considering an option which has payoff function $\max\{S_T-\frac1\tau\int_0^\tau S_t\mathrm{d}t,0\}$ for a fixed $\tau$ in the risk-neutral measure $\mathrm{d}S_t/S_t=r_t\mathrm{d}t+\sigma_t\mathrm{d}W_t^\mathbb{Q}$. I have a few questions:

- What is the name of this kind of option? This looks like an arithmetic average floating strike Asian call, but if I recall correctly for usual Asian options the integral runs from $0$ to $T$ instead of $\tau$. (Please let me know if I have missed something on this SE, I’ll remove this question if it is redundant!)

- Does the price of this option have a closed form solution? I know the conventional arithmetic Asian call does not, which is why I am quite hesitant to go through the potential rabbit hole to solve for $\mathrm{e}^{-r(T-t)}\mathbb{E}^\mathbb{Q}(\max\{S_T-\frac1\tau\int_0^\tau S_t\mathrm{d}t,0\}|\mathcal{F}_t).$ I'm assuming there should be different considerations for $t\in[0,\tau)$ and $t\in[\tau,T)$.

Any guidance is appreciated!

## Answer by Soumirai (score 2)

https://quant.stackexchange.com/a/60131

- It would be an Asian strike call option, with the Asianing being computed over some period $[0;\tau]$. Not a big deal that the average is not computed from 0 to T. It even seems more natural to be done that way in practice.

- Before $\tau$, pricing would be similar to your option Asianing until T. For $t>=\tau$, you already know the value of the Asian strike though (it is $F_\tau$-measurable), so its pricing would be like any European call.

Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)

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