Pricing and Hedging of American Knock-In Options FARID AITSAHLIA, LORENS IMHOF, AND TZE LEUNG LAI FARID AITSAHLIA American barrier options of the knock-in type involve as they do not have closed-form solutions, is a senior scientist at non-Markouian optimal stopping problems for early unlike their European-style counterparts (see DemandTec in Stanford, CA. exercise. They therefore cannot be priced via stan- Merton [1973] and Rubinstein and Reiner farid @stat.stanford.edu dard methods such as binomial or trinomial trees [1991]). LORENS IMHOF and finite-difference schemes for free-boundary par- Naive application of the Cox-Ross- is an assistant professor at tial differential equations. Rubinstein binomial tree method for barrier Institut ftir Statistik und options has been shown by Boyle and Lau Wirtschaftsniathematik in This article provides a modified tree method to [1994] to yield inaccurate values, even with Aachen, Germany. price these options. It also develops fast and accu- many steps. To address this problem, which
[email protected] rate analytic approximations for the price and hedge stems from the position of the barrier relative TZE LEUNG LAI parameters. to the grid, a number of variants of the tree is a professor of statistics at method have been advanced. Stanford University. omplex derivatives have become Ritchken [1995] implements a trinomial
[email protected] accepted instruments to tailor risk tree method. Cheuk and Vorst [1996| develop coverage for risk managers and a time-dependent shift for the trinomial tree, Cinvestors. Barrier-type options and Figlewski and Gao [1999[ introduce an have become important instruments, particu- adaptive mesh model that grafts high-resolution larly for the valuation of structured products lattices around points that cause the inaccuracies (see Banks [1994]).