Risk and Decision Making · Options Trading Guide
A high win rate does not establish a profitable strategy. Combine the size of wins, losses and costs, then examine outcomes beyond the average.
Define exactly what is being estimated
Probability of profit depends on the payoff, costs, horizon and model. It differs from the probability that an option expires in the money or touches a strike during its life. Delta is primarily a local price sensitivity. Treating its magnitude as a precise real world probability ignores assumptions and distinctions between pricing and actual outcome distributions.
Combine frequency and size
Imagine a simplified strategy wins $100 on 80% of trades and loses $500 on 20%. Gross expectancy is 0.80 × $100 minus 0.20 × $500 = a $20 loss per trade. Costs make it worse. The frequent premium collections can feel reassuring while the arithmetic remains unattractive. This hypothetical distribution is not a forecast for any named option strategy.
Test the loss distribution
Average losses can hide a small number of much larger outcomes. Ask whether the sample includes stress periods, gaps and realistic forced exits. A credit strategy that looked stable during calm conditions may have little evidence about rare losses. Model uncertainty should remain visible, especially if the measured advantage disappears after a modest change in assumed loss frequency or execution costs.
Avoid confusing a model with permission to trade
A positive estimated expectancy does not guarantee a profitable next trade or a tolerable drawdown. Dependence between trades, changing conditions and position size affect the account’s path. Compare results after all costs and report sample size. Build a decision rule that can reject an apparently attractive probability when the downside, liquidity or funding requirements are incompatible with the portfolio.
Try it yourself
A hypothetical strategy wins $200 on 60% of trades and loses $250 on 40%. Costs average $8 per trade. What is estimated net expectancy?
Show the worked answer
Gross expectancy is $120 minus $100 = $20. After $8 of costs, estimated net expectancy is $12 per trade. The assumed probabilities and payoff distribution still require evidence.
Further reading
Educational material. Examples and rates are hypothetical, not trade recommendations. Product terms, eligibility and risks vary by venue and jurisdiction.
