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Modeling Option Liquidity with Implied Volatility Spreads

Article Quant Q&A · Author: quant_dev
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Summary

The note explains how to represent liquidity in options using the bid–ask spread. A wider spread indicates lower liquidity, while a narrower spread indicates higher liquidity. The spread can be measured in price units or converted into implied volatility terms.

Implied volatility spreads can support more consistent comparisons of liquidity across options and hypothesis testing, because they express the bid–ask difference on a volatility scale. The document points to a research paper as an example of this approach but provides no empirical findings or detailed estimation procedure. It does not discuss how to account for other liquidity dimensions, such as market depth or trading costs, so the spread should be understood as a proxy rather than a complete measure.

Key ideas

  • Bid–ask spreads are a common proxy for instrument liquidity.
  • A wider option spread generally signals lower liquidity.
  • Option spreads can be expressed in price units or implied volatility units.
  • Implied volatility spreads can make cross-sectional liquidity comparisons more consistent.

Tags

OptionsVolatilityMarket microstructureStatistics
Full text
# Modeling liquidity effect on option prices


# Modeling liquidity effect on option prices












What are practically useful ways of modelling the effect of liquidity on options?

## Answer by glyphard (score 4)

https://quant.stackexchange.com/a/1245

In general liquidity is most often modeled, for most types of instruments, via proxy by the 'bid-ask spread' (wider = less liquid, narrower = more liquid)

You can choose to model the bid-ask spread in dollars, or what is often most helpful, for options, is to model the bid-ask spread in terms of implied volatility (of the difference between the bid and ask prices). This lets you make consistent cross-sectional comparisons of liquidity, and do hypothesis testing.

here's a sample paper that uses the implied vol appraoch: http://www.ccfr.org.cn/cicf2010/papers/20091215131015.pdf

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.