Normal Distribution Options Rule
Match neutral options tactics to ordinary ranges and hedge extreme deviations
- Difficulty
- Expert
- Time to result
- ~ongoing to results
- Steps
- 5
- Confidence
- 94%
Dorsey applies the normal distribution to choose a portfolio posture. Because roughly sixty-eight percent of observations fall within one standard deviation of the middle, he argues that the baseline response should often be neutral rather than aggressively directional. His neutral tactic is covered writing: own the security or portfolio and sell calls against it to collect income while prices remain around the center. He then uses the same chart to identify an extreme. When a holding reaches roughly three standard deviations above trend, the probability of movement back toward the middle supports selling a call against the position. A major downside move requires either new covered writing or a predefined stop-loss response. The mechanism is explicitly bounded: Dorsey rejects naked options because their risk is too large relative to the reward.
Origin
Dorsey says statistics 101 and the normal distribution shaped his options thinking, and that his models display a normal distribution beside each chart.
Core principles
- 01Most observations cluster near the middle of a normal distribution.
- 02A neutral market expectation should use a neutral options strategy.
- 03Covered writing limits risk compared with naked options positions.
- 04Extreme deviations increase the probability of movement back toward trend.
- 05A distribution informs a rule; it does not guarantee an outcome.
How to run it
- 1
Map the distribution
Estimate the current trend and standard-deviation bands for the instrument or portfolio. Locate price relative to the center and the outer bands.
Pro tip Update the estimate as trend and volatility evolve.
Watch out A stale or poorly estimated distribution gives false precision.
- 2
Choose the neutral baseline
When the position sits in the broad middle, consider covered writing as the neutral strategy. Own the underlying asset before selling the call.
Pro tip Match the option exposure to the quantity actually owned.
Watch out A covered call still leaves substantial downside exposure in the underlying asset.
- 3
Respond to an upper extreme
When price reaches roughly three standard deviations above trend, treat mean reversion as more probable and sell a covered call against the position.
Pro tip Define the standard-deviation threshold before the price reaches it.
Watch out An extreme reading can persist and does not guarantee immediate reversion.
- 4
Plan the downside
Specify whether a meaningful decline leads to another covered-writing decision or to a stop-loss exit. Make the rule part of the strategy before the decline occurs.
Pro tip Model the loss in the underlying separately from option income.
Watch out Premium income does not eliminate equity drawdown risk.
- 5
Keep exposure bounded
Avoid naked straddles and other uncovered positions in this implementation. Reassess the distribution and obligations throughout the option's life.
Pro tip Use only position sizes whose assignment and downside outcomes are manageable.
Watch out Uncovered options change the framework from bounded portfolio management to open-ended risk.
In the wild
Dorsey describes a chart with a normal distribution shown beside it. When the stock moves to the top band, about three standard deviations above trend, the investor sells a call against the owned position because the probability favors movement back toward the middle.
→ The investor applies a predefined covered-call response to an extreme rather than making an unbounded bearish bet.
Common mistakes
Treating probability as certainty
A high standard-deviation reading raises a probability; it does not promise immediate mean reversion.
Selling naked options
Dorsey explicitly rejects naked exposure because of its unfavorable risk relative to reward.
Ignoring underlying downside
Covered-call income does not prevent the owned security from losing value.
Is it for you?
Best for
It is best for experienced investors who already own diversified securities and understand covered-call obligations and downside risk.
Not ideal for
It is not ideal for inexperienced options users, assets without defensible distribution estimates, or anyone considering naked positions.
From the transcript
“if sixty eight percent of the time everything is middle, and what's the right strategy that will be a neutral strategy.”
“the covered right is the one strategy that's a neutral strategy.”
“if you see it move up to where it says top your three standard deviations above trend, that's telling you the stock has done well,…”
From the episode
Interview With Tom Dorsey: Masters in Business (Audio)
Tom Dorsey