In: Finance
As per Put Call Parity, the prices of options with same strike price & expiry date are as follows:
Price of Call + PV of Exercise Price = Spot Price (Current Stock Price) + Price of Put
Interest Rate is assumed as continuous compounding
2.56 + [40*(e^-0.06*4/12)] = 38 + P
2.56 + [40*(e^-0.02)] = 38 + P
2.56 + [40*0.9802(from table)] = 38 + P
Therefore, No Arbitrage Price of Put = P = 2.56 + 39.208 - 38 = $3.768
b)
Actual Price of Put < Theoretical Price. Therefore, Put is Undervalued.
Arbitrage Strategy:
As Put is Undervalued, Sell Call Option, Borrow, Buy Stocks Now and Buy Put Option
Steps for Arbitrage:
Now,
(1) Sell (Write) Call Option at $2.56
(2) Borrow (Cost of Put + Current Spot Price - Inflow from Call) = (2.95+38-2.56) = $38.39 for 4 months @6%
(3) Buy share @ $38
(4) Buy Put Option at $2.95
Balance = 2.56+38.39-38-2.95 = 0
After 4 months,
Case 1: If Stock Price is less than $40, then Exercise Put and Lapse Call. Stock will be sold for $40 under Put contract.
Case 2: If Stock Price is greater than $40, then Exercise Call and Lapse Put. Stock will be sold for $40 under Call contract.
Case 3: If Stock Price is equal to $40, then Both Lapse. Stock will be sold for $40 in Market
Therefore, In any Case, we will be able to sell the stock for $40
(5) Sell share @ $40
(6) Repay the loan along with interest i.e. 38.39*e^0.02 = 38.39*1.0202(from table) = $39.17
Balance = Arbitrage Gain = 40 – 39.17 = $0.83