Final answer:
The correct expression for the payoff on the described call option on Heating Degree Days is 'min($10,000 × max(Total HDD – 4500, 0), $1,000,000)', which calculates the payoff based on the total HDD exceeding the strike value, up to a maximum payoff limit.
Step-by-step explanation:
The expression for the payoff on a weather option, specifically a call option on Heating Degree Days with a strike of 4500 and a tick size of $10,000, can be described as the minimum of the product of $10,000 and the maximum of the total Heating Degree Days minus the strike, and the maximal limit payoff. Since a call option profits when the underlying exceeds the strike, the proper expression for the payoff is: Payoff = min($10,000 × max(Total HDD – 4500, 0), $1,000,000)
This means that if the total Heating Degree Days are above the strike of 4500, the payoff will be $10,000 times the amount by which it exceeds the strike, up to a maximum of $1,000,000. If the total Heating Degree Days are below the strike, the payoff is $0, as the 'max' function would result in 0. The 'min' function then ensures the payoff doesn't exceed the capped amount of $1,000,000.