In finance, a debit spread, a.k.a. net debit spread, results when an investor simultaneously buys an option with a higher premium and sells an option with a lower premium. The investor is said to be a net buyer and expects the premiums of the two options (the options spread) to widen.
Investors want debit spreads to widen for profit.
A bullish debit spread can be constructed using calls. See bull call spread.
A bearish debit spread can be constructed using puts. See bear put spread.
A bull-bear phase spread can be constructed using near month call & put.
The maximum gain and loss potential are the same for call and put debit spreads. Note that net debit = difference in premiums.
Maximum gain = difference in strike prices - net debit, realized when both options are in-the-money.
Maximum loss = net debit, realized when both options expire worthless.