本文藉由外生性質押限制的調整，以事件分析的方式剖析董事質押行為的改變。實證結果顯示質押限制規範的落實顯著降低了質押者的質押比例；尤其是高度質押的董事不但會下修其質押比例，更將其質押比例調整至接近50%的門檻。質押比例下修的行為確實透露了質押者仍在乎過度質押所可能造成之表決權的喪失。換言之，在質押行為潛藏著質押者之責任與利益不對等的前提下，限制質押比例的政策明顯抑制了質押者的自利行為。

In Taiwan, public firms are mandatorily required to restrict the proportion of pledged shares held by directors since 2011. This criterion offers a natural opportunity with exogenous change of policy to examine the behavior of pledging shares. Our empirical findings indicate that the percentages of pledged shares do decrease significantly after the implementation of this requirement. In particular, for those directors with pledged shares over 50% of their initial holdings before this restriction, the percentages of their pledged shares appear to be just slightly under the 50% threshold after then. In short, restricting the proportion of pledged shares does lower the incentive of pledging behavior.