Expected Value

Expected value (EV) is the average outcome of a trade if it were repeated many times. It is calculated by multiplying each possible outcome by its probability and summing the results. A positive expected value means the trade is mathematically favorable over time. A negative expected value means you lose money on average, regardless of any individual trade's result.

Why It Matters

Expected value is the most important concept for any trader who wants to be consistently profitable. A single trade can win or lose regardless of its EV, but over dozens or hundreds of trades, your results will converge toward the expected value. This is why professional traders focus on process over outcomes — they want every trade to have positive EV, knowing that the math will work in their favor over time.

Many traders focus exclusively on win rate, but win rate alone is misleading. A strategy that wins 90% of the time but loses 10x the average win on each loss has negative EV. Conversely, a strategy that wins only 30% of the time but makes 5x the average loss on each win has strongly positive EV. Expected value accounts for both probability and magnitude.

How It Works

The basic EV formula for a trade with two outcomes (win or lose):

EV = (Probability of Win x Win Amount) - (Probability of Loss x Loss Amount)

For an options trade, this becomes:

EV = (P(profit) x Average Profit) - (P(loss) x Average Loss)

Calculating EV for common strategies:

For a short put spread collecting $1.50 on a $5-wide spread:

• Max profit: $1.50 (probability estimated from delta or pricing model)
• Max loss: $3.50 ($5.00 width - $1.50 credit)
• If probability of profit is 70%: EV = (0.70 x $1.50) - (0.30 x $3.50) = $1.05 - $1.05 = $0.00

An EV of zero means the market is pricing the trade fairly — no edge for buyer or seller. This is common because options markets are efficient. Positive EV typically comes from having a better estimate of probabilities than the market, or from systematically exploiting behavioral edges.

Sources of positive EV:

• Selling options when IV is higher than future realized volatility (volatility risk premium)
• Buying options when IV is lower than expected realized volatility
• Having a directional thesis that differs from market consensus
• Capturing structural edges (such as earnings IV overpricing)
• Managing positions actively (rolling, adjusting) to improve average outcomes

EV is not certainty: A positive EV trade can still lose money — even several times in a row. EV only matters over a large sample size. This is why position sizing and risk management are essential alongside positive EV trade selection.

Quick Example

You sell a $5-wide iron condor for $2.00 credit. Your max profit is $2.00 and max loss is $3.00. You estimate (based on IV percentile and historical analysis) that this trade profits 65% of the time with an average profit of $1.60, and loses 35% of the time with an average loss of $2.20.

EV = (0.65 x $1.60) - (0.35 x $2.20) = $1.04 - $0.77 = $0.27 per share

Over 100 trades, you expect to net roughly $0.27 x 100 x 100 = $2,700 (before commissions). That is positive EV — a mathematical edge that compounds over time.