# Payoff at expiry for the purchase of a put option

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## Description

Formula for calculating the payoff of a long position in a put option.

## Formula

$R_{lp}=max\left ( -P+(K-S_{T}),-P \right ) \$

## Legend

 $K\$ Option strike price $P\$ Value of the option premium $S_{T}\$ Price of the underlying at expiry date T of the option