# What is Dual Delta?

I understand that it is the partial derivative of option price with respect to strike. What is it used for though? What does your dual delta signify?

• Well, let's see. In the BSM model the Dual Delta of a Call is $e^{-rT}N(d_2)$. Look familiar? – noob2 Apr 20 '17 at 2:14
• I would say it is the price of an Arrow Debreu security that pays 1 USD at time T if the Call is in the money and 0 otherwise. – noob2 Apr 20 '17 at 2:22