| Abstract: | 本計畫首先以一寡佔數量模型分析當其中一位管理者為過度自信時, 該廠商可能採取一先佔性的高產量. 當面臨需求變動時(正向或負向), 由自信管理者所管理的廠商所面臨的衝擊較大. 其次, 本計畫以美國2008-2012年(全球金融危機)之廠商別資料, 以選擇權來衡量過度自信, 實證結果發現, 約53.05％的有效樣本歸類為過度自信. 我們進一步將樣本區分為新舊兩群：舊的自信管理者指的是那些已經於1993-2003 被Hirshleifer et al. (2012)歸類為過度自信的管理者, 而新的自信管理者指的是那些於蕭條時期新產生的自信管理者. 結果發現, 不同於Hirshleifer et al 的結果, 本計畫發現股票波動性和管理者過度自信在全球金融危機期間為負相關, 此外, 管理者過度自信在三各面向的廠商績效評量部分均有正的影響：獲利率（靜態）, 股票波動性（穩定）及銷售成長（動態）.
Our paper presents a simple Cournot model where one of the two managers overestimates the market demand. We demonstrate that the firm run by overconfident manager can pre-dominate the market by producing a large amount of output. When there is a demand shock (positive or negative), the positive or negative impact will be higher with the firm operated by an overconfident manager. Next, we analyses the firm-level data of U.S.A. during the 2008-2012 global financial crisis. According to the “options exercise measure“ for managerial overconfidence, 2634 CEOs, 53.05% of the effective samples, are classified as “overconfident“. Our research further considers two subgroups: Old overconfident CEOs who were already classified as overconfident during 1993-2003, and New overconfident CEOs who only emerge as overconfident CEOs during 2008-2012. The Old overconfident CEOs are defined so that we can investigate the fame effect of overconfidence, and make a comparison to Hirshleifer et al. (2012) who conclude that stock return volatility is positively related to managerial overconfidence during 1993-2003, while our results suggests that stock return volatility is negatively related to managerial overconfidence during the global financial crisis. Overall, our results identify positive strategic impacts of managerial overconfidence on three aspects of performance: profitability (static), stock return volatility (stability) and sales growth (dynamic). |
