看跌期权是什么？在学习CFA过程中是不是需要掌握这个知识呢？考题是怎样的呢？小编给你说说这个知识！
An investor writes a put option with an exercise price of $40 when the stock price is $42. The option premium is $1. At expiration the stock price is $37. The investor will realize:
A a loss of $2.
B a loss of $3.
C a profit of $1.
【答案及解析】A Because the stock price at expiration is less than the exercise price, the buyer of the put option will exercise it against the writer. The writer will have to pay $40 for the stock and can only sell it for $37 in the market. However, the put writer collected the $1 premium for writing the option, which reduces the net loss to $2.
【核心词汇 】put： 看跌期权
是指一类期权。即期权合约持有人有权利在合约规定的时间按一定的价格向对方卖出基础资产。
B-S模型是看涨期权的定价公式，公式表示为：
S+PE(S，T，L)=CE(S，T，L)+L(1+γ)-T
移项得:PE(S，T，L)=CE(S，T，L)+L(1+γ)-T-S，将B-S模型代入整理得：P=L·E-γT·[1-N(D2)]-S[1-N(D1)]此即为看跌期权初始价格定价模型。
C—期权初始合理价格
L—期权交割价格
S—所交易金融资产现价
T—期权有效期
r—连续复利计无风险利率H
σ2—年度化方差
N()—正态分布变量的累积概率分布函数
