Understand the net Greeks of a bull call debit spread and how they change as price moves between the long and short strikes.
Positive delta
The long lower-strike call usually has more delta than the short higher-strike call, leaving positive net delta. Delta may increase as price enters the spread, then shrink as both calls become deep ITM.
Gamma and curvature
The long call contributes positive gamma and the short call negative gamma. Net gamma changes with price and time, so the spread's directional response is not constant.
Theta and vega
A bull call spread often begins with modest negative theta and positive vega, both smaller than a standalone long call. Their signs can change in some price regions, especially near expiration.
Rho and position scale
Interest-rate exposure is generally modest and partly offset. Multiply every quoted Greek by signed quantity and contract multiplier, and recalculate as the underlying, IV and time change.
A practical example
If the long call has delta 0.58 and the short call has delta 0.27, the spread has about +0.31 net delta, or roughly +31 share equivalents per standard spread.
This simplified example focuses on the spread at a specific moment and expiration outcome. Live option prices also reflect the underlying price, time decay, rates, dividends, liquidity and transaction costs. Greeks are theoretical estimates, not guarantees.
Frequently asked questions
Is delta always positive?
It is normally positive for a standard bull call spread, but approaches zero at extreme prices.
Does the spread have theta decay?
Often yes, though less than the long call alone and not with a fixed sign everywhere.
How is net vega calculated?
Subtract the short call's vega from the long call's vega.
Continue the Bull Call Spreads cluster
Explore related guides: How Implied Volatility Affects a Bull Call Spread · Bull Call Spread: 12 Mistakes to Avoid · How to Choose Bull Call Spread Strikes. For a structured sequence, use the free Level 9 – Bull Call Spread Strategy course.
Options involve risk and are not suitable for every investor. This material is educational and is not investment, tax or legal advice. Greeks are theoretical estimates, and contract terms and broker requirements can vary.