營利事業所得稅率調降與實質盈餘管理之關聯性研究

Abstract

有鑑於民國98年5月1日，立法院三讀通過所得稅法修正案，將營利事業所得稅率從25%調降至20%，並改採單一稅率制，自99年度起適用。由於此調降幅度可減輕企業相當可觀之租稅負擔，可能使管理者產生高度之誘因將98年度之盈餘向下管理。故本研究探討管理者是否於98年度採用加速裁決性費用及降低生產成本的方式向下管理盈餘。另外，本研究也預期98年課稅所得越高之公司，其盈餘管理之程度將越大。 本研究引用Roychowdhury（2006）之模型估計異常裁決性費用、異常生產成本用，藉以衡量企業盈餘管理之傾向，並進一步以輔助實證模型檢視98年盈餘管理於99年度之迴轉現象。 實證結果發現，企業於稅率調降之前一年度（98年度）會操縱裁決性費用與生產成本，以將盈餘向下管理，並且將於99年度有顯著迴轉現象。而98年度課稅所得越高的公司，於98年度向下盈餘管理程度越大。

The Legislative Yuan of Republic of China passed an amendment to the Income Tax Act in May 2009, which reduced the corporate income tax rate from 25% to 20% and the amendment applied to 2010 onwards. This income tax rate reduction would provide managers with large motivations to manage earnings downward in 2009 so the enterprise can minimize the tax burden. This study investigates whether corporation management manipulates earnings downward by accelerating discretionary expenses and decreasing production costs in 2009. In addition, this study expects the degree of this real earnings management for firms with higher 2009 taxable income to be greater. This study employs Roychowdhury（2006）model to estimate the abnormal discretionary expenses and abnormal production cost as a measure of real earnings management. I find evidence consistent with managers manipulating discretionary expenditures and production cost to minimize the income tax in 2009 and a significant reversal of real earnings management measures in 2010. The degree of this real earnings manipulation is higher for companies with higher taxable income in 2009.The result provide evidence suggesting that companies conduct real activity earnings management to move earnings to future period in which the tax rate is low to alleviate tax burden.