Abstract
An adjusted Black-Scholes pricing formula is derived in this paper. By separating risk and uncertainty through the robust control technique, we find thatuncertainty as well as risk raises the management’s subjective evaluation of real options. We suggest a simple method to filter the risk of the project and to acquire a more reliable value of real options without the influence of uncertainty. Besides, we propose that one investment opportunity may be postponed inappropriately, since under uncertainty the exercise of investment may be delayed by the project manager.