半導體產業上市櫃公司買回庫藏股之宣告效果研究

Abstract

文獻上對於公司買回庫藏股之宣告效果進行實證研究者眾多，且多偏向所有產業相互間比較分析，較無針對單一產業及其特殊產業結構，做相關實證研究，例如:半導體產業上、中、下游公司。2006年5月24日，經濟部針對員工分紅之會計處理為與國際接軌，修正發布商業會計法第64條不得作為公司費用之規定，僅侷限於對業主分配，對於此影響半導體員工薪資福利甚鉅新法規公布之後，半導體公司宣告庫藏股其影響為何。 本文有別於以往之做法，針對自2000年8月9日正式實施庫藏股制度後，至2008年4月20日為止，所有購回自家股票之上市櫃上、中、下游110家半導體設計、製造、封測公司為研究樣本，採用事件研究法進行各個分類構面之實證研究。本研究區分半導體公司宣告買回庫藏股之短期與長期持續性、不同買回目的、買回比率、員工分紅費用化制度公布前後差異與半導體公司上、中、下游產業結構特性等進行檢定。 實證結果發現，在庫藏股宣告之短期與長期效果中，買回宣告後不論長期或短期皆有正向之累積異常報酬；依庫藏股申報之目的區分，以維護公司信用及股東權益為目的之宣告效果最為顯著；依買回股數占總發行股數比率來區分，可發現購回比率越高之半導體公司，其宣告後平均異常報酬越為顯著；依員工分紅費用化制度公布前後區分，公布前平均異常報酬較為顯著；依半導體公司上、中、下游產業結構區分，以半導體設計業之庫藏股宣告效果較為顯著。以上結果可提供半導體公司在進行股票購回決策時之參考，以及投資人與主管機關對庫藏股實施效益的評估依據。

According to literature review on announcement effect of share repurchase, all of them focus on empirical study and gap analysis in different industries rather than specific one industry and it’s structure differentiation such as semiconductor upstream、midstream and downstream company. To align with international GAAP (Generally Accepted Accounting Principles), Ministry of Economic Affair revised commerce accounting law article 64 to expense employee bonus on May 24, 2006. This revision poses a big impact on employee’s salaries and welfare those who work in semiconductor industries. Is there any impact to announcement effect of share repurchase after this law revision? This study is different from before, using event study for empirical study and focusing on listed 110 semiconductor design, manufacture and testing companies started from the date of August 9, 2000 to April 20, 2008. It will test following characters by following categories: short-term and long-term continuous effect, different purposes, buyback rate, before and after employee bonus expensing law and semiconductor design、manufacture and testing company. The empirical results are as following : There are positive cumulative abnormal return for announcement effect of both short-term and long-term；The purpose for protection of company reputation and shareholder’s equity has more significant effect than other purposes； The higher of buyback rate the more significant of average abnormal return； Bonus expensing law before revision is more significant than after on announcement effect of share repurchase；Semiconductor Design Company is more significant than other manufacture and testing company. The results can be reference for Semiconductor Company manager when they want to perform share repurchase and performance index reference for stakeholder and government.