When executing a vertical spread, what must be true about the strike prices?

In a vertical spread, the key requirement is that the options have different strike prices but share the same expiration date. This strategy involves buying one option (either a call or a put) and simultaneously selling another option of the same class (call or put) with a different strike price, while both options expire on the same date. This allows the trader to capitalize on the price movements of the underlying asset within a defined range, providing a limited risk and potential profit scenario.

The other options do not align with the fundamental mechanics of a vertical spread. Having equal strike prices would not create a spread, as there would be no difference to exploit. While reflecting market trends can guide which strike prices to select, it is not a strict requirement for the execution of a vertical spread. Additionally, including options from different asset classes would go against the definition of a vertical spread, which necessitates that the options belong to the same asset class. Therefore, the requirement that the strike prices vary while sharing the same expiration is crucial for executing this specific option trading strategy effectively.