# Mean reversion with options

**OPT-08 · Core Options · Core**

**Lesson question:** When does a return-to-value idea fit the auction?

Original fictional examples; educational writing, not live market data, orders or production approval.

## By the end

- Explain the mechanism in the lesson question.
- Reproduce the worked comparison and recognize its failure case.

**Prerequisites:** OPT-F01, OPT-F02, OPT-F03, OPT-F04

Mean reversion is a hypothesis that an excursion will return toward a reference such as a prior balance, VWAP or volume POC. The hypothesis needs a rejection mechanism and a time horizon, not just a large recent move.

A market can become more expensive and remain accepted there. An extreme is not automatically an entry.

## Understand the mechanism

A debit spread can target a measured return, while a credit spread can express that an extension will not hold. The same directional thought creates different payoff, IV and time exposures in those structures.

A reference such as VWAP is an average from a declared window, not fundamental value or a price the market owes you.

## Walk through the process

Mark the level before the test. Look for a failed extension and a defined invalidation, then compare executable option prices with the expected target and time. Avoid fading genuine acceptance merely because an indicator is stretched.

Study the ticket and stress a continued trend, including assignment and expiry mechanics for short legs.

## Contract and decision boundary

Terminal examples use simultaneous intrinsic realization of all stated legs, before unspecified costs. Actual American exercise, assignment, early liquidation and broker handling can create different interim cash needs. These fictional comparisons are education, not orders or personalized investment advice.

## A worked example

Fictional spot moves from a balanced 100 to 103, fails to hold above a premarked 102 boundary and returns to 101.50. A bearish return-to-100 thesis is now different from selling the first print at 103.

Suppose a 105/110 call credit spread pays 1.00. At common expiry it earns at most 100 and can lose 400 per 100-unit spread before costs. The favorable technical hypothesis does not eliminate that asymmetry. The graph shows this exact terminal position.

## Graph: Mean reversion with options—worked comparison

**Horizontal:** Underlying at common expiry (USD)  
**Vertical:** Call-credit spread terminal P/L (USD)

Fictional data from the written example. The chart organizes the comparison; its shape is not a forecast.

Complete numerical data are embedded in `scripts/options-strategies/OPT-08.js` and displayed as an accessible table in the HTML lesson.

## What would invalidate the reading?

A trend keeps accepting higher prices while the trader repeatedly sells calls on the theory that price is too high. A new credit does not fix an invalidated auction thesis.

## Check your understanding

### What is maximum terminal loss on a five-point call credit spread paying one point?

**Answer:** 400 per 100-unit spread before costs.

**Why:** Width minus credit, with common-expiry settlement assumptions.

### What is the critical failure to avoid?

**Answer:** A trend keeps accepting higher prices while the trader repeatedly sells calls on the theory that price is too high. A new credit does not fix an invalidated auction thesis.

**Why:** Explain this risk before treating the example as a decision rule. A correct calculation does not guarantee a favorable market outcome. **Critical risk check.**

## Takeaway

Return to the question: When does a return-to-value idea fit the auction? State the observed facts, the assumptions and the failure condition separately.

## References and provenance

The cited references support definitions and conventions. The teaching prose, tickets and numerical scenarios are original; they are not attributed as historical market observations.

- [OCC Options Disclosure Document](https://www.theocc.com/company-information/documents-and-archives/options-disclosure-document)

- [OIC Strategy Reference](https://www.optionseducation.org/strategies/all-strategies-en)