本論文擴充 Stiglitz (1977) 的最適保險理論 , 建立保險獨占市場下的兩期動態模型 ,
分析最適動態保險契約。 我們發現在充分資訊下 , 最適動態 / 兩期保險契約無異於最適靜
態 / 單期保險的 「複製」 契約 , 不論高風險或低風險客戶 , 都獲得完全保險 , 且兩期保費固
定不變。 而在資訊不對稱的情況下 , 購買動態保單的低風險客戶雖與靜態保單一樣獲得不
完全保險 , 不過第二期的保險不完全程度 ( 與保費 ) 則依據客戶的 「事故史」 調整 , 與前期
的契約條件出現差異。

The thesis extends Stiglitz’s (1977) optimal insurance theory with monopoly,
and establishes a two-period dynamic model to induce an optimal dynamic insur-
ance contract. We found that under perfect information, the optimal dynamic (two-
period) insurance contract is nothing but a "copy" of the optimal static (single-
period) contract, that is, regardless of differences in the type of risk, every customer
buys a type-dependent policy that provides full insurance each period and the pre-
miums for which are fixed across periods. In the case of information asymmetry,
although customers of low-risk type obtain only incomplete insurance as in the static
model, the dynamic incomplete coverages against losses (and premiums for which)
will be provided differently between periods, and, moreover, those contract terms
for the second-period be set contingent to the first-period’s history of accidents.

論文審定書 i
中文摘要 ii
英文摘要 iii
符號對照表 v
1 緒 論 1
2 最適保險契約 : Stiglitz (1977) 靜態模型 4
2.1 充分資訊下的最佳 (first-best) 保險契約 . . . . . . . . . . . . . . . . . . 5
2.2 資訊不對稱下的次佳 (second-best) 保險契約 . . . . . . . . . . . . . . . 7
3 充分資訊下的動態保險契約 11
3.1 最佳動態契約的基本模型 . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.2 最佳動態契約的特性 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4 資訊不對稱下的最適動態保險 17
4.1 高風險客戶的最適保費與自負額 . . . . . . . . . . . . . . . . . . . . . . 20
4.2 低風險客戶最適保費與自負額 . . . . . . . . . . . . . . . . . . . . . . . 21
5 結論 24
參考文獻 26

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