Bull Call Spread options strategy

What is a bull call spread?

A bull call spread is a two-leg vertical spread built by buying a call at a lower strike and selling a call at a higher strike, both on the same underlying and with the same expiration. Because the trader pays more for the lower-strike call than they collect for the higher-strike call, the position opens for a net debit. That debit is the most the trade can lose. In exchange for a lower cost than a standalone long call, the trader accepts a ceiling on profit: gains stop growing once the underlying reaches the short strike.

The strategy is often called a debit call spread or a long call vertical. It expresses a moderately bullish view with risk and reward that are both known on the day the trade is opened.

When to use it and the market view

A bull call spread fits a view that the underlying will rise, but not necessarily explode higher. If you believe a stock trading near $200 could reach roughly $210 over the next month, paying for unlimited upside through a long call may be inefficient. Selling the 210 call gives away gains above that level, which you did not expect to capture anyway, and uses the premium to lower both cost and breakeven.

The structure is also useful when implied volatility is elevated. A long call alone is expensive when IV is high, and a fall in IV after a catalyst can hurt it even if the price moves in your favor. Because the spread is long one option and short another, much of that volatility exposure offsets. Strike selection matters: a narrow spread is cheaper but caps profit quickly, while a wider spread costs more and needs a larger move to reach its maximum value.

Payoff, formulas, and a 200 strike example

Let S be the underlying price at expiration, K1 the lower (long) strike, K2 the higher (short) strike, and D the net debit per share.

Profit = max(S − K1, 0) − max(S − K2, 0) − D

Breakeven = K1 + D · Maximum profit = (K2 − K1) − D · Maximum loss = D

Suppose you buy the 200 call for $8 and sell the 210 call for $4. The net debit is $4 per share, or $400 per contract before fees. Walk through several expiration prices:

• S = 195: both calls expire worthless. Profit = 0 − 0 − 4 = −$4 per share, the maximum loss.
• S = 204: the long call is worth 4, the short call is worthless. Profit = 4 − 0 − 4 = $0. This is the breakeven.
• S = 207: profit = 7 − 0 − 4 = +$3 per share ($300 per contract).
• S = 215: profit = 15 − 5 − 4 = +$6 per share ($600 per contract), the maximum.

Every dollar above 210 adds a dollar to the long call and a dollar of liability to the short call, which is why the payoff line goes flat above the short strike. The trade risks $400 to make up to $600, a reward-to-risk ratio of 1.5 to 1.

Maximum profit, loss, and breakeven

Measure	Formula	200/210 spread, $4 debit
Maximum profit	(K2 − K1) − debit	$6 per share ($600 per contract) at or above 210
Maximum loss	Net debit	$4 per share ($400 per contract) at or below 200
Breakeven at expiration	K1 + debit	$204

These values apply at expiration. Before then, the spread usually trades at less than its full value even when the underlying is above the short strike, because the short call still holds time value.

Greeks and implied volatility impact

The spread has positive delta, but less than a single long call because the short call offsets part of it. Delta is usually highest when the underlying sits between the strikes. Gamma is positive near the long strike and turns negative near the short strike, so the position becomes less responsive as it approaches maximum value.

Theta depends on where the price is. When the underlying is near or below the long strike, time decay usually works against you. When it is near or above the short strike, decay can help because the short call's time value falls faster. Net vega is small. A rise in IV slightly helps the spread when it is out of the money and slightly hurts it when it is deep in the money. That offset is the main reason traders choose a spread over a long call before events that often crush implied volatility.

Risks to manage

The maximum loss is capped at the debit, but losing the full debit is common if the underlying fails to rise before expiration. If the short call is in the money, it can be assigned early, especially before an ex-dividend date. Your long call still covers the obligation, but assignment can create a stock position and margin effects you need to handle. Wide bid-ask spreads on two legs can reduce returns, so use limit orders. Many traders plan to close before expiration rather than hold through settlement, to avoid pin risk when the price finishes near the short strike.