DEBIT SPREADS VS CREDIT SPREADS

Plain English

Think of two neighboring parking spaces. A debit spread is like renting the prime space for $10 and subletting the less convenient one for $6 — you're out a net $4 and hope demand rises so the price gap widens in your favor. A credit spread reverses the roles: you lease out the prime space for $10 and rent the cheaper one for $6, collecting $4 upfront. You profit if demand stays flat or falls and no one exercises the lease. In options terms, the 'spaces' are strikes, the 'rents' are premiums, and the changing gap between them is the spread's mark-to-market value.

Going deeper

A vertical spread pairs one long and one short option of the same type and expiration but different strikes. Debit spread: buy the higher-priced leg, sell the lower-priced leg → net cash outflow. Credit spread: sell the higher-priced leg, buy the lower-priced leg → net cash inflow. Let W = strike width, D = debit paid, C = credit received. Debit spread: Max Loss = D, Max Profit = W − D, Breakeven = Long-leg strike ± D. Credit spread: Max Profit = C, Max Loss = W − C, Breakeven = Short-leg strike ± C (add for calls, subtract for puts). Theta: debit spreads are negative theta (need expansion to profit), credit spreads are positive theta (benefit from time decay). Delta aligns with directional bias: a bull call debit and bull put credit both carry positive delta, making them directionally equivalent even though one pays you and one costs you.

Examples