本文將特定的模型錯置形式加入 Cochrane and Saa-Requejo’s (2000) 中，推導出不完備市場中具有穩健性質的訂價區間。在資產價格服從幾何布朗運動之下，本文模型不僅對於考量不確定性的投資人的決策有意義，且對於歐式買權具有方便分析的封閉解。此外，以一個標的物資產無法在市場被交易的指數選擇權為例，利用我們的模型訂價具有許多值得探討的性質，相較於 Cochrane and Saa-Requejo’s (2000) 的訂價區間，我們發現在特定的模型錯置形式下，會有足夠多的實際價格落入我們推導出的訂價區間。

In this paper, we extend the analysis of Cochrane and Saa-Requejo (2000) to deriving good-deal bounds on asset prices when investors worry about model uncertainty and seek robust pricing decisions in incomplete markets. Under the assumption that asset prices are driven by geometric Brownian motion processes, we propose a framework that is meaningful and very natural for investors' decision problems involving uncertainty about the pricing models, and derive closed-form solutions for the pricing bounds of the European option. We investigate properties of the proposed pricing bounds and apply these bounds to value a European option whose underlying asset is a non-traded stock index. We find that, under certain circumstances of model uncertainty, the proposed pricing bounds can contain sufficient amounts of the actual option prices, which is in contrast with the empirical finding of the good-deal bounds proposed by Cochrane and Saa-Requejo (2000).

1 前言 1
2 不完備市場訂價模型回顧 4
2.1 Gain-loss 資產訂價模型 4
2.2 Good-deal 資產訂價模型 6
2.2.1 離散時間模式 7
2.2.2 連續時間模式 9
3 Good-deal bounds 的台指選擇權實證分析 12
4 模型不確定性 15
4.1 Ellsberg Paradox 15
4.2 模型不確定性的文獻回顧 18
5 考量模型錯置下的 Robust good-deal bounds 23
6 Robust good-deal bounds 的台指選擇權實證分析 27
7 結論與建議 29
A 附錄 31
A.1 考慮模型錯置的價格區間推導 – 以歐式買權為例 31
參考文獻 35

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