過去使用現金流量折現法衡量公司價值，往往都是藉由調整折現率以反映未來不確定性因素，但是，如此一來便忽略了在不確定性情況下，企業經營可能因有限責任之組織型態，而有獲利潛力無窮但下方風險有限之特性。近年來，許多文獻開始運用實質選擇權貼水衡量專案或公司價值，以反映經理人在面臨情況改變時，可以改變策略以降低損失或增加利潤的實務狀況。本研究運用實質選擇權理論與資本預算模式，分別就自由現金流量、經濟附加價值及傳統會計盈餘等三種不同定義之現金流量，以連續時間模型衡量我國電子業上市公司之合理價值，並檢視上述三種不同定義之現金流量在考慮不確定性因素下的估價績效表現。本研究實證結果發現，考慮不確定性下自由現金流量折現法較其他模型為佳；其次，放棄選擇權的貼水與平減後市值間呈負相關。

Previous studies dealt with corporate valuation under uncertainty by adjusting discounted rate. However, these models failed to recognize asymmetric payoffs between upside and downside situations due to corporation's limited liability characteristics. An increasing number of researchers apply real-option theory to value a project or a company in considering of the decision flexibility while managers facing the situation of changing environments. This paper employs real-option theory and capital budgeting techniques to get the theoretic market price of electronic listed companies and compares the fitness of valuation modeling by different definitions of cash flow, such as free cash flow, economic value added, and accounting earnings. Our evidence shows that the free cash flow real-option model performs very well among different models and the value of abandon option is negatively related to deflated market value of the firm.