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Modeling Short-Dated Option Risk with Limited Price History

Article Quant Q&A · Author: user3079
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Summary

The document considers how to estimate portfolio risk when short call positions have only a brief pricing history, alongside bonds, currencies, and stocks. Its central recommendation is to model the risks that drive option values rather than extrapolating a short option-price series backward along rolling maturities.

For near-expiry options, the response highlights changes in the underlying asset price as the main risk input and volatility as another relevant input. It suggests repricing the calls under scenarios for the underlying, using a pricing model. It does not provide a specific extreme-risk statistic, backtest, or quantitative evidence, so the guidance is conceptual. It also cautions that longer-dated options may require modeling how the volatility surface moves with the underlying, a substantially more complex task; the simplified approach may therefore omit important risks in other settings.

Key ideas

  • Option portfolio risk can be assessed through the inputs that determine option value instead of relying on a short option-price history.
  • Underlying price changes are a primary risk driver for short-dated calls.
  • Volatility remains relevant and can be incorporated by repricing options under scenarios.
  • Longer-dated options may require modeling volatility-surface dynamics linked to the underlying.

Tags

OptionsVolatilityRisk managementDerivatives pricing
Full text
# How do I model risks for specific short-term short calls in a portfolio with limited data?


# How do I model risks for specific short-term short calls in a portfolio with limited data?












I'm trying to do some risk analysis on a portfolio of bonds, currency, stocks and short calls. The short calls expire in approximately 15-30 days and I've only got around 20 days of pricing data on them. Can I extrapolate the call positions into the past on a rolling maturity basis so that I can look at how a portfolio containing calls would've performed in the past? How are extreme risks generally measured with limited data e.g. 30 day options?

## Answer by Brian B (score 5, accepted)

https://quant.stackexchange.com/a/4320

It doesn't make sense to use option price series data for computing option risk anyway. Since they are derivatives (i.e. their value is derived from other securities) it is more basic and reasonable to handle the underlying risks.

As hinted by John, the risks to an option portfolio are generally considered in the context of inputs to a pricing model (which may be as simple as the Black-Scholes formula). The most important of these is underlying price, and the second most important is volatility.

When options are short-dated like yours, there is not usually much volatility value left in them. Therefore the risk could reasonably be captured simply by making sure your risk model considers changes in the option underlying, and repricing options accordingly.

If you had longer-dated options, you would certainly want some model of volatility surface dynamics linked to stock prices. That is a far more complex undertaking.

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.