The barrier shift prices an option monitored every with the continuous formula at the barrier , moved away from the spot, with .
उदाहरण
Example 15.13 (How good is the shift)
The knock-out call of Example 15.9 (barrier 90) is worth 7.23 with continuous monitoring. With daily monitoring, a Monte Carlo of 200 000 paths gives 7.48 (standard error 0.03), and the shifted formula 7.45. With weekly monitoring they give 7.62 and 7.68, with monthly 8.01 and 8.04, and with four dates 8.33 and 8.38 (Figure 15.3, right). For an up-and-out call with barrier 120, where the payoff is large at the barrier, the shift is good daily (1.26 against 1.28) and poor quarterly (2.19 against 2.50). The correction is an expansion in and fails when the barrier is within a few steps of the spot or the payoff at the barrier is large.