Figure 1. The stock price trend of Apple Inc.
As shown above, Apple Inc’s stock price had small
reduction from Jun. 1st, 2022, to Jun.28th,2022, from
$148.71 to $138.44. there was some minor volatility
as Apple's share price declined during the study
period.
2.2 Method
The Black-Scholes formula is used as a model for
valuing European or American call and put options on
a non-dividend paying stock. In option pricing theory,
the Black-Scholes equation is one of the most
effective models for pricing options (Mehrdoust,
2014). Black Scholes model take into account the risk
factor of the underlying stock, the strike price of the
option contract, the initial stock price and the time
value of money, which are all significant factors,
while pricing each option contract. Its
comprehensiveness and completeness also enhances
its accuracy while computing different option prices.
All options have limited downside and rely on price
volatility for upside, thus a rise in volatility raises the
value of both calls and puts (Yacine, 2003). However,
the Black Scholes model, similar to other option
pricing models, is not a perfect one as well. In fact,
there are some unrealistic assumptions that the Black
Scholes model makes in order for its convenience of
computation and conciseness. First, the Black Scholes
model assumes that volatility of the stock and the
market’s risk-free rate are all constant throughout the
whole maturity time, which is not true in the real case.
Second, the Black Scholes model also assumes that no
option could be exercised before the maturity time,
which makes it only effective while pricing European
option contracts. Third, the Black Scholes assumed
that the market is a frictionless one, which means there
would not exist any transactional costs while trading
these financial derivatives, which is also unrealistic,
too. Last but not least, although all these up-mentioned
assumptions might affect the accuracy of the Black
Scholes model, we could not deny that it is still one of
the most common and conservative way for pricing
European option contracts.
Options Spread is a trading strategy for options in
the financial market that entails taking opposite
directional positions in the price of a pair of options
belonging to the same asset class but with different
strike prices and expiry dates. A spread position
involves two options with distinct strike prices and
expiry dates (Abhilash, 2021). The hedging strategy is
completed with two steps in the research as below.
First, the implied volatility of the stock is calibrated
with the price of the stock and that of ten options as
selected, on the stock using Black Scholes model.
Second, applying the implied volatility calculated, a
hedging strategy is constituted for a chosen option on
the stock.
Following on, the implied volatility utilized in the
Black-Scholes model is an estimated value estimated
by calculating the market stock prices’ standard
deviation or other estimating and forecasting
techniques such as maximum likelihood estimation,
moment estimation, generalized linear model,
Bayesian point estimation. In our study, we decided to
estimate the volatility in two different ways: the
traditional market stock prices’ standard deviation and
minimizing the difference between real market option
price and Black-Scholes price calculated utilizing the
Black-Scholes formula. The whole pricing process
stars as the following. First, we choose the 2022 June
1st AAPL open price as our initial stock price S (0).
Second, we choose five different call options and put
120
125
130
135
140
145
150
6,01 6,06 6,09 6,14 6,17 6,23 6,28
Appe Inc.