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Bull Call Spread

You think BTC is going higher over the next two weeks. A naked 92k call costs 5,200 and bleeds 180/day in theta. You are paying for unlimited upside you probably do not need. The bull call spread fixes this: buy the call you want, sell a cheaper call above it to offset the cost. You cap your upside, but you cut the price tag in half and the theta bleed along with it.

Also called a debit call spread because you pay net premium at entry.

What You Do​

The SetupYou pay premium
Buy1 call at the lower strike (K1)
Sell1 call at the higher strike (K2), same expiry
Max Profit
Width - debit
Max Loss
Net debit
Breakeven
K1 + net debit
Margin
Net debit paid; short leg margined pre-expiry

How the P&L Works​

Three zones at expiry:

  1. Below K1. Both calls expire worthless. You lose the entire net debit. This is the scenario you sized for.
  2. Between K1 and K2. Your long call gains intrinsic value, the short call is still OTM. Profit grows dollar for dollar with spot.
  3. Above K2. Both calls are ITM. Every dollar gained on the long call is offset by the short call. P&L is capped at max profit.

Worked Example: BTC 92k/98k Bull Call Spread​

BTC at 93,400. 14 DTE. IV at 62%.

Buy 92k call at 4,850. Sell 98k call at 1,700. Net debit: 3,150. Width: 6,000.

BTC at Expiry
Long $92k Call
Short $98k Call
P&L
$88,000
$0
$0
-$3,150
$92,000
$0
$0
-$3,150
$95,150
+$3,150
$0
$0
$96,500
+$4,500
$0
+$1,350
$98,000+
+$6,000+
offsets
+$2,850

Max profit: 2,850 (width 6k minus 3,150 debit). Max loss: 3,150. Risk/reward: 0.9:1. Breakeven: 95,150.

You need BTC above 95,150 at expiry to make money. That is a 1.9% move from entry. Not asking for the moon, just a modest grind higher.

Explore the Payoff​

Spot at Expiry$100k
$70k$130k
Net Debit$4k
$1k$9k
BE $99k$0+$6k-$4k$70kK1 $95kK2 $105k$130kSpot Price at ExpiryP&L
Settlement
$100k
P&L
+1.0k
Max Loss
-$4k
Max Gain
+$6k

When to Use​

  • Moderately bullish. You think BTC goes up, but you are not calling for a face-ripping rally. If you think it is going from 93k to 130k, just buy the call.
  • You want to reduce cost. The short leg subsidizes the long leg. In the example above, selling the 98k call cut the cost from 4,850 to 3,150, a 35% discount.
  • IV is elevated and you want to offset some vega exposure. You are long vega on one leg and short vega on the other. They partially cancel.
  • You want defined risk on both sides. No margin calls. No surprise at 3 AM when BTC drops 12%.
💡

The bull call spread partially hedges vega. If IV drops after entry, the short call also loses value, and since you sold it, that helps you. This makes spreads more forgiving than naked long options when IV crushes after a catalyst. You are not immune to vol crush, but you are wearing a seatbelt.

Greeks at a Glance​

Greek
Sign
What It Means
Delta
+
Net positive but lower than a naked call. You are paying for less directional exposure.
Gamma
+/-
Positive near K1 (good -- delta accelerates into the move), negative near K2 (gains slow down).
Theta
+/-
Negative when spot is near K1 (time works against you), flips positive near K2 (short leg decays faster).
Vega
Low
Long and short legs partially cancel. You still have some net long vega, but much less than a naked call.
Common Mistakes
The mistakeChoosing a spread too narrow for the expected move. "It's only $1,500 wide, so it's cheap!" -- yes, and it needs a precision landing to pay off.
The realityWidth should reflect your realistic price target. If you think BTC moves $5k, a $2k-wide spread means you need the move AND tight timing. Go wider or accept the binary-bet nature.
The mistakeIgnoring the gap between theoretical fill and what you actually get on both legs. The model says net debit is $3,150 but you fill at $3,400.
The realitySpread orders have two bid/ask spreads working against you. Always use a limit order on the net spread price. If you leg in separately, you are exposed to the market moving between fills.
The mistakeHolding to expiry when you have captured 80% of max profit with 5 days left. Greed for the last 20% is not worth the gamma risk.
The realityNear expiry, small spot moves can swing you from near-max-profit to breakeven. Take the win. Close the spread and redeploy.

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