# Bull Call Spread: Net Debit, Breakeven, Capped Profit, and Assignment

Build a bull call debit spread, calculate its expiration payoff and breakeven, and manage volatility, execution, and assignment risks.

Canonical: https://wiki.fcontext.com/options/bull-call-spread/
Fact checked: 2026-07-22

> For educational purposes only; not investment advice.

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## Direct answer

A **bull call spread**, or call debit spread, buys a call at a lower strike and sells a call at a higher strike with the same underlying, expiration, exercise style, settlement, multiplier, and quantity. It is normally opened for a net debit and expresses a view that the underlying will rise toward or above the short-call strike by expiration.

Maximum contractual loss is the initial net debit. Maximum expiration profit is `strike width − net debit`, multiplied by the contract multiplier. The short higher-strike call reduces entry cost but sells away gains above that strike.

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## Expiration payoff and changing sensitivities

Let the long-call strike be `K_L`, the short-call strike `K_H`, with `K_L < K_H`, and net debit `D`. Profit per underlying unit at expiration is:

`max(S_T − K_L, 0) − max(S_T − K_H, 0) − D`

- If `S_T ≤ K_L`, both calls have no intrinsic value and loss is `D`.
- If `K_L < S_T < K_H`, profit rises dollar for dollar as spot rises.
- If `S_T ≥ K_H`, spread value is capped at `K_H − K_L`, so maximum profit is `(K_H − K_L) − D`.
- Expiration breakeven is `K_L + D`, before fees.

Before expiration, the spread generally has positive delta and gamma. Net theta and vega depend on spot, time, and each strike's implied volatility. Selling the higher call often reduces negative theta and positive vega compared with an outright call, but it does not eliminate either sensitivity.

American-style short calls can be assigned early, particularly when deep in the money with little extrinsic value and around an ex-dividend date. Assignment creates short shares; the lower-strike long call remains a separate contract and may still contain time value.

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## 100/110 call spread example

Suppose one 100 call costs `$6.50` and one 110 call is sold for `$2.50`, using the same expiration and a 100-share multiplier. Net debit is `$4.00`.

- Maximum loss: `$4.00 × 100 = $400`.
- Strike width: `$110 − $100 = $10`.
- Maximum profit: `($10 − $4) × 100 = $600`.
- Expiration breakeven: `$100 + $4 = $104`.

At a `$95` expiration price, both calls have no intrinsic value and loss is `$400`. At `$105`, the long call is worth `$5` and the short call zero, so profit is `($5 − $4) × 100 = $100`. At `$115`, the spread is worth `$10`, producing the maximum `$600` profit.

If the underlying rises far above `$110`, profit remains capped. That forgone upside is the economic price of the `$2.50` premium received from the short call.

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## Trade and expiration checklist

- Confirm both legs match in underlying, expiration, exercise style, settlement, multiplier, and quantity.
- Use the executable complex-order debit; two favorable leg midpoints may not trade together.
- Convert debit, profit cap, fees, and stress losses into account dollars.
- Compare with the outright call, including the upside surrendered above `K_H`.
- Inspect liquidity and volatility skew at both strikes.
- Stress a slow rise, sharp rise, no move, decline, volatility crush, and widening spreads.
- Monitor short-call extrinsic value and early-assignment risk, especially near dividends.
- Near expiration, plan for pin risk and unintended shares if only one leg is exercised or assigned.

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## Common misconceptions

- “A bullish view guarantees profit.” The move must exceed debit, arrive in time, and survive execution costs.
- “The short call is free financing.” It pays premium by surrendering upside above its strike.
- “Maximum loss prevents other account demands.” Early assignment can create 100 short shares per standard contract.
- “Higher volatility always helps.” Relative volatility changes at both strikes determine the net effect.
- “Maximum profit is the expected return.” It is one endpoint with no probability weighting.
- “Rolling repairs the original trade.” It closes one spread and opens another at new prices and terms.

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## Related topics

- [Vertical Spreads](/options/vertical-spread/)
- [Assignment Risk](/options/assignment-risk/)
- [Bid-Ask Spread](/options/bid-ask-spread/)

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## Authoritative sources

- [Characteristics and Risks of Standardized Options](https://www.theocc.com/company-information/documents-and-archives/options-disclosure-document) - Options Clearing Corporation
- [Bull Call Spread (Debit Call Spread)](https://www.optionseducation.org/strategies/all-strategies/bull-call-spread-debit-call-spread) - Options Industry Council
- [Options](https://www.finra.org/investors/investing/investment-products/options) - FINRA