本文以傳統抵換理論模型的觀點,探討內部負債對於公司最適資本結構的影響,藉以說明過去文獻中所提槓桿過低的迷思(Low-Leverage Puzzle, e.g. Graham, 2000)主要是因為並未考慮公司的內部負債,因而高估公司的最適槓桿。實證結果顯示,公司內部負債與公司槓桿會呈現負向相關,而且當公司退休金提撥越充分,公司的資金使用會比較有彈性以及較多的舉債空間,因而減弱內部負債對最適槓桿的負向影響。此外,實證結果亦顯示,公司的內部負債會影響其資本結構的調整速度,1985年至2012年間以及2007年至2012年間整體的調整速度在考慮內部負債後都有明顯的變快;當以未考慮內部負債的目標槓桿分成低於和高於目標槓桿兩個子樣本後,前者的調整速度和整體的變化是一致的,但2007年至2012年調整速度低於目標槓桿的公司是變慢、高於目標槓桿的公司則是變快。
This study examines the effects of inside debts on a firm's target leverage and explains the low-leverage puzzle (e.g. Graham, 2000) by the over estimation of the target leverage due to neglecting the effects of inside debts. We find that a firm’s inside debt affects not only the target leverage, but also the speed of adjustment toward that target. A firm’s target leverage is negatively related to the amount of inside debt and the effect of inside debt is alleviated when a firm’s funding status is positive. Additionally, the adjustment speeds are faster when considering inside debt effects during 1985-2012 and 2007-2012. If we separated the whole sample firms into below- and above- traditional target leverage, we find that adjustment speeds are slower (faster) when firms have below-target (above- target) leverage after 2007.