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ROBUST BOUNDS FOR FORWARD START OPTIONS
Author(s) -
Hobson David,
Neuberger Anthony
Publication year - 2012
Publication title -
mathematical finance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.98
H-Index - 81
eISSN - 1467-9965
pISSN - 0960-1627
DOI - 10.1111/j.1467-9965.2010.00473.x
Subject(s) - straddle , upper and lower bounds , mathematical economics , mathematics , stochastic game , embedding , log normal distribution , call option , economics , econometrics , mathematical optimization , computer science , financial economics , statistics , mathematical analysis , artificial intelligence
We consider the problem of finding a model‐free upper bound on the price of a forward start straddle with payoff . The bound depends on the prices of vanilla call and put options with maturities T 1 and T 2 , but does not rely on any modeling assumptions concerning the dynamics of the underlying. The bound can be enforced by a super‐replicating strategy involving puts, calls, and a forward transaction. We find an upper bound, and a model which is consistent with T 1 and T 2 vanilla option prices for which the model‐based price of the straddle is equal to the upper bound. This proves that the bound is best possible. For lognormal marginals we show that the upper bound is at most 30% higher than the Black–Scholes price. The problem can be recast as finding the solution to a Skorokhod embedding problem with nontrivial initial law so as to maximize .