BOSS

Bull Call Spread

Description

Buying a lower-strike call and selling a higher-strike call in the same expiry, trading away unlimited upside for a lower cost of entry.

Setup

  1. Buy one call at a lower strike.
  2. Sell one call at a higher strike, same expiry.

Context

Used when you expect a moderate rise and want a cheaper, defined-risk alternative to a bare long call.

Risk Profile

Maximum loss is the net debit paid. Maximum gain is the difference between strikes minus that debit, reached once the underlying is at or above the higher strike.

Pros

  • Costs less than an outright long call.
  • Defined, capped risk.
  • Less exposed to a drop in implied volatility than a bare long call.

Cons

  • Gain is capped even if the underlying rallies hard.
  • Still needs the underlying to clear the lower strike plus net debit to profit.

Effect of Time

Time decay is muted compared to a single long call, since the short call's decay partially offsets the long call's decay.

Effect of Volatility

The spread's net vega is small; a change in implied volatility has a limited effect since both legs move together.

Look-Alike Strategies

Live Structure

Live
Index price: $84519.0700
PositionRightRatioStrikeExpiryPremiumFill PriceEst. Fee
Long Call 1 $84000.0000 24 Sep 2026 $612.8831 $760.8204 $25.3607
Short Call 1 $85000.0000 24 Sep 2026 $88.7611 $76.0809 $11.0951
Net Cost$524.1220
Delta0.5542
Gamma-0.0001
Vega-0.5526
Theta-7.0914
Rho0.4663
Breakeven(s) $84524.1220

Estimated Cost to Assemble

An estimate of what entering this structure right now would really cost: filling every leg by crossing the spread (the ask when buying, the bid when selling) instead of at the mid-price, plus an estimated exchange fee. Real fees and fills can differ from this estimate.

Mid-Price Cost$524.1220
Slippage+$160.6175
Execution Cost$684.7395
Estimated Fees+$36.4558
Total Estimated Cost$721.1953

Payoff & Greeks vs. Underlying Price

The Greeks curves are a Black-Scholes model using each leg's current implied volatility, holding time to expiry fixed -- not live exchange data at every price, which only exists at the current price (dashed line).

Payoff at Expiration

This structure's value and profit/loss at expiration, at a handful of specific prices: every leg's strike, every breakeven, the current spot, and the chart's own range.

Underlying PriceValue at ExpirationProfit / LossReturn on Cost
$83000.0000 $0.0000 -$524.1220 -100.0%
$84000.0000 $0.0000 -$524.1220 -100.0%
$84524.1220 breakeven $524.1220 $0.0000 +0.0%
$84534.3600 current $534.3600 $10.2380 +2.0%
$85000.0000 $1000.0000 $475.8780 +90.8%
$86000.0000 $1000.0000 $475.8780 +90.8%

Delta (model)

Gamma (model)

Vega (model)

Theta (model)

Rho (model)