Options Academy
Ratio Call Spreads 102: The Math & Margin
Two numbers matter most: max profit at the short strike, and upside break-even beyond it. Margin comes from the naked call portion.
Core Formulas (2:1)
Points of Max Profit: Net credit + strike spacing (or spacing - net debit).
Upside Break-even: Higher strike + points of max profit.
In the 40/45 example: spacing is 5, credit is 1, so max profit is 6 points and break-even is 45 + 6 = 51.
Strike Spacing
5 points
Net Credit
1 point
Max Profit
6 points ($600)
Upside Break-even
$51
General Ratio Formulas
For any ratio, the logic is the same but scaled by the number of long calls.
Max Profit Points: Net credit + (Long calls x strike spacing).
Upside Break-even: Higher strike + (Max Profit Points / naked calls).
Long Calls
L
Short Calls
S
Naked Calls
S - L
Break-even
High strike + max profit / (S - L)
Why Margin Matters
A ratio call spread includes a naked call. That is where margin comes from.
Rule of thumb: margin is roughly 20% of stock price + call premium - out-of-the-money amount.
With stock at $44 and the $45 calls at $3, that is 20% of 44 ($8.80) + $3 - $1 = $10.80 ($1,080).
The $1 credit reduces the requirement to about $980.
20% of $44
$880
Call Premium
+$300
OTM Amount
-$100
Net Margin
$980
Collateral to the Break-even
A conservative approach is to fund enough margin to reach the upside break-even.
Using $51: 20% of $51 = $1,020, plus $600 intrinsic value, less the $100 credit = $1,520.
20% of $51
$1,020
Intrinsic at $51
+$600
Credit Offset
-$100
Suggested Collateral
$1,520
Ratio Comparison (Same Prices)
Using XYZ $44, 40 calls at $5, and 45 calls at $3, ratios behave differently:
Higher ratios boost credit but lower the upside break-even and increase upside risk.
3:2 Ratio
Debit 1 | Upside BE 54 | Max Profit 9
2:1 Ratio
Credit 1 | Upside BE 51 | Max Profit 6
3:1 Ratio
Credit 4 | Upside BE 49.5 | Max Profit 9
Downside BE
Only 3:2 has downside BE (~40.5)
Key takeaways
- Max profit equals strike spacing plus net credit (or minus debit).
- Upside break-even is the higher strike plus max profit points.
- Margin is driven by the naked call portion of the spread.
- Keep extra collateral to avoid forced actions if the stock rallies.
Series
Ratio Call Spread Masterclass
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