Consider a market with a risk-free bond B, for which Do = 50, = 55, Primer on Pricing Risky Securities 81 and 82 = 60, and a risky stock with the spot price So = 50. Suppose that the stock price at times t = 1 and t = 2 can follow four possible scenarios:
Scenario S1 S2
w1 60 70
w2 60 55
w3 45 45
w4 45 40
(a) Find an arbitrage investment strategy if there are no restrictions on short selling.
(b) Is there an arbitrage opportunity if no short selling of the risky asset is allowed?