reference:

A stock trades at $20. Its annual volatility is 18%. The risk-free rate is 3%. Calculate the price of a European call option and put option with strike K = 20 and T equal to 4 months. 206 CHAPTER 11. THE GREEKS 2.

(Continued) Calculate the of a portfolio consisting of 2 long calls and 1 short put from the previous problem. How many shares of the stock would you short in order to build a new portfolio that is delta-neutral? 3.

(Continued) If the stock moves down 15 cents, what is the exact change in price of the delta-neutral portfolio from the previous problem? 4.

(Continued) What is the of one of these calls? of one of the puts?

Question:

(Continued) Calculate the and the of a straddle built from one of the calls and one of the puts. This example illustrates why a straddle built from at-the-money options is close to being delta-neutral and is a bet on volatility.