本文研究概念參考Cook, Moser, and Omer (2017)探討企業租稅規避與權益資金成本之關聯，權益資金成本估算則依據Hou, Van Dijk, and Zhang (2012)使用橫斷面模型預測未來盈餘，透過四種模型計算權益資金成本。採用臺灣2000年至2018年上市及上櫃企業資料，檢驗是否企業租稅規避程度偏離投資者預期愈大，投資人未來現金流風險及機會成本愈大，導致權益資金本提高。研究結果發現，無論是以產業年度中位數或五年自我迴歸模型衡量的預期避稅水準，皆可發現租稅規避偏離度和權益資金成本有正向關聯。
本文進一步參考Goh, Lee, Lin, and Shevlin (2016)以財務限制指標、資訊品質與公司治理，分別探討不同指標對於租稅規避偏離度之調節效果。在調節作用下，大部分的租稅規避偏離度與權益資金成本之正向關係，會受到高財務限制、高資訊品質及良好的公司治理而強化，該結果普遍符合假說所預期。最後，為解決內生性問題進行改變分析，實證結果亦顯示避稅偏離度與權益資金成本仍呈現顯著正相關。

This paper aims to investigate the association between tax avoidance and the cost of equity capital in Taiwan. Based on Cook, Moser, and Omer (2017), this paper develops two proxies for investor’s expectations of tax avoidance and explores whether deviations from those expectations result in a higher cost of equity capital. We find that the cost of equity capital increases with tax avoidance that is deviated from investor expectations. This effect is stronger for firms that are highly financially constrained, firms with better information quality, and firms with better company governance. Our results indicate that equity investors generally require a higher expected rate of return due to the negative cash flow effects of corporate tax avoidance. To further mitigate the concern of omitted variables driving our results, we utilize a change regression specification for our main analyses in additional sensitivity test and the results support our main conclusion. Overall, these findings are consistent with the Scholes and Wolfson trade-off framework and reinforce the notion that an effective tax strategy involves evaluating not only the benefits from tax savings but also non-tax costs.

第壹章 緒論 1
第一節 研究動機與背景 1
第二節 研究方法 3
第三節 研究流程 5
第貳章 文獻探討與假說 6
第一節 租稅規避 6
第二節 權益資金成本 7
第三節 假說建立 10
第參章 研究方法 14
第一節 樣本篩選與資料來源 14
第二節 租稅規避指標 15
第三節 權益資金成本估算 17
第四節 實證設計 26
第肆章 實證結果 32
第一節 權益資金成本估算結果 32
第二節 樣本敘述統計 36
第三節 迴歸結果分析 43
第四節 額外測試 61
第伍章 結論 66
第一節 結論與建議 66
第二節 研究限制 67
參考文獻 69

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