這篇論文包含兩項研究成果：其一為檢驗分期分級董事會制度對於公司勞動力投資效率的影響；其二為資安攻擊事件對公司避稅活動的影響。 第一項研究使用西元1997年至2015年的美國資料作為研究分期分級董事會制度與勞動力投資效率之關聯性的研究樣本。實證研究顯示，採用分期分級董事會制度的公司將展現出較佳的勞動力投資效率，該制度將使得公司降低其異常淨招募額(包含過度招募與招募不足)。此外，兩者間的正向關係在CEO工作高度穩定、高人力資本密度、低勞動調整成本與年輕公司中尤為明顯。總體而言，本研究成果為分期分級董事會制度的正面效益給予強力的支持，再次體現該制度不僅可使公司管理階層專注於股東的長遠利益，連帶也將激勵公司方重視並改善勞動力投資的效率。 第二項研究藉由配對樣本並利用雙重差分法來探討資安攻擊事件對公司避稅活動的影響。實證研究發現，經歷過資安攻擊事件的公司偏好較低的現金有效稅率、從事避稅活動的可能性較高，並有著較高之會計所得與課稅所得間之課稅差異。進一步研究指出，資安攻擊事件對於避稅活動的影響程度，在高財務危機風險及資訊不對稱的公司之中更加明顯。進一步分析亦指出，在曾頒布資訊保護法的州之中，避稅活動可能性的上升幅度較大；而在高資安投資額的公司之中，避稅活動可能性的上升幅度卻較微小。綜合以上所述，公司在經歷資安攻擊事件後，將在稅務上採取較具風險性的行為以因應較高的財務危機風險與資訊不對稱. ;This thesis contains two studies that examine the impact of staggered boards on labor investment efficiency and the impact of cyberattacks on tax aggressiveness. In the first essay, I use comprehensive U.S. data from 1997 to 2015 to investigate the relationship between staggered boards and labor investment efficiency. The study documents that firms with staggered boards exhibit greater labor investment efficiency. Staggered boards benefit firms by reducing abnormal net hiring under both forms of over-investment (over-hiring and under-firing) and under-investment (under-hiring). The positive relation between staggered boards and labor investment efficiency is more pronounced for firms with high CEO job security, high human capital intensity, low labor adjustment costs, and young age. Overall, the results lend strong support to the view that staggered boards strengthen managers’ commitment to long-term shareholders’ interests, thereby encouraging managerial effort in boosting labor investment efficiency. In the second essay, I investigate the impact of cyberattacks on tax aggressiveness using a difference-in-differences analysis with a matched sample. I find that firms experiencing cyberattacks are more likely to have lower cash effective tax rates, a higher likelihood of engaging in tax-sheltering activities, and greater discretionary book-tax differences. Further analyses show that cyberattacks have a greater impact on corporate tax aggressiveness when firms are more exposed to financial distress and information asymmetry. Additional analyses show that tax aggressiveness increases more when firms are in states with enactments of notification laws, but increases less in firms with higher cybersecurity investment. The aggregate results suggest that firms take more tax risky positions in response to greater financial distress and information asymmetry, which are attributed to the consequences of cyberattacks.
