The four basic verticals
- Bull call spread (debit): buy a call, sell a higher call.
- Bear put spread (debit): buy a put, sell a lower put.
- Bull put spread (credit): sell a put, buy a lower put.
- Bear call spread (credit): sell a call, buy a higher call.
The math
Debit spread: max loss is the debit, max profit is the width minus the debit. Credit spread: max profit is the credit, max loss is the width minus the credit.