What it means
The strategy is built from two legs. Buying the lower-strike call gives the right to buy the asset at that price, and selling the higher-strike call brings in premium that partly offsets the purchase, in exchange for giving up any gain above the higher strike.
Because the sold call reduces the upfront cost, the position is a net debit spread: you pay to put it on, and that payment is the most you can lose. This is the appeal for someone who is moderately bullish and wants defined risk rather than an open-ended bet.
The trade-off is the ceiling. If the asset soars past the higher strike, the profit stops there, so the strategy suits a view that the price will rise by a specific, moderate amount rather than a view that it might triple.
The three numbers to know before entering are the net debit, the maximum profit, which is the gap between the strikes minus the net debit, and the breakeven, which is the lower strike plus the net debit. Every decision about which strikes to choose is a trade between the cost of the spread and how far the price has to move for it to pay.
Time and volatility work differently than they do for a single bought call. The sold leg partly offsets time decay and reduces sensitivity to falling implied volatility, which is why traders often prefer spreads when options look expensive.
In practice
Real-world examples.
Example
An investor holds a view that a retailer's shares will rise moderately after a trading update but does not want to risk a large premium. With the share at $48 she buys the $50 call and sells the $55 call for a net $1.80, risking $180 per contract for a possible $320.
Example
A fund manager wants exposure to a possible recovery in an energy stock but is constrained by a risk limit expressed in maximum loss per position. A bull call spread lets him take the position with a known, capped downside that fits inside the limit, which an outright share purchase would not.
Example
A trader notices implied volatility on a biotechnology stock has risen sharply ahead of a regulatory decision, making single calls expensive. He uses a bull call spread so that the inflated premium he pays on the bought leg is partly recovered by the inflated premium he receives on the sold leg.
Formula
Calculation
Net debit = Premium paid on the lower strike call - Premium received on the higher strike call. Maximum profit = (Higher strike - Lower strike) - Net debit. Maximum loss = Net debit. Breakeven = Lower strike + Net debit. Suppose a share trades at $48 and you expect it to reach the mid-fifties within three months. You buy one three-month $50 call for $3.00 per share and sell one three-month $55 call for $1.20 per share, and each contract covers 100 shares. Net debit is $3.00 - $1.20 = $1.80 per share, or $180 for the contract pair. Maximum profit is ($55 - $50) - $1.80 = $5.00 - $1.80 = $3.20 per share, or $320. Maximum loss is the $180 paid. Breakeven is $50 + $1.80 = $51.80. If the share finishes at $57, both calls are exercised, the spread is worth the full $5.00 per share, and the profit is $5.00 - $1.80 = $3.20 per share or $320, a return of $320 / $180 = 178% on the amount risked. If the share finishes at $49 or below, both calls expire worthless and you lose the full $180.Case study
Seen in the real world.
Bramfield Asset Management is an invented firm used purely for this illustrative example. Its small-cap team was bullish on a listed engineering group trading at $48 ahead of an expected contract award, but the fund's mandate capped any single speculative position at $200,000 of potential loss.
Rather than buy 4,000 shares outright, the team placed 1,000 bull call spreads, buying the $50 calls at $3.00 and selling the $55 calls at $1.20, for a net outlay of 1,000 x 100 x $1.80 = $180,000. That sat inside the mandate, and the maximum gain if the shares closed above $55 was 1,000 x 100 x $3.20 = $320,000.
The contract was awarded and the shares closed the quarter at $61. The spread paid its maximum, delivering $320,000 on $180,000 at risk, although an outright share position would have earned considerably more. This fictional case illustrates the central bargain of the strategy: you accept a ceiling on the upside in return for a floor on the loss and a much smaller upfront cost.
Watch out
Common mistakes.
- Forgetting that the profit is capped, then feeling cheated when the share price runs far past the higher strike and the position stops gaining.
- Choosing strikes so far apart that the spread costs almost as much as an outright call, which gives up upside without meaningfully reducing the cost.
- Ignoring dealing costs, since a spread involves two legs on entry and potentially two on exit, and on small positions those charges can consume a large slice of the maximum profit.
Questions
People also ask.
When should you use a bull call spread instead of buying a call?
When you expect a moderate rise to a level you can name, and especially when option premiums look expensive, because the sold leg recovers part of that cost.
What happens at expiry if the price sits between the two strikes?
The bought call has value and the sold call expires worthless, so the position is worth the share price minus the lower strike, which may be a partial profit or a partial loss depending on the net debit.
Can you close a bull call spread early?
Yes, both legs can be traded out at any time before expiry, and traders often close early to capture most of the profit rather than carry assignment risk into the final days.
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