What Is the Maximum Theoretical Delta for a European Call Option?

The maximum theoretical Delta for a European call option is 1. Delta is the first derivative of the option price with respect to the underlying asset price.

A Delta of 1 signifies that the option's price will move dollar-for-dollar with the underlying asset. This occurs when the option is deep In-the-Money (ITM) and has very little time remaining until expiration.

At this point, the option behaves essentially like a long position in the underlying asset, as exercise is virtually guaranteed.