會計方法選擇與盈餘管理：以折舊方法為例

The Choice of Accounting Methods and Earnings Management: The Case of Depreciation Method

本文是利用不對稱資訊與訊號模式，考慮好壞兩種公司於不同破產成本下，分別導出成功與失敗公司會選擇相同折舊方法而無法揭露公司真實型態之混合均衡條件，以及成功公司所選擇之折舊方法不同於失敗公司，藉以誠實揭露公司型態時之分離均衡條件。為了驗證資本市場的實際現象是否與理論模式的結果一致，本文以新上市公司為例，探討影響管理當局的會計方法選擇（以折舊提列方法為例）的因素。此外，本文亦進一步將應計項目分為裁決性當期應計項目、非裁決性當期應計項目、裁決性長期應計項目與非裁決性長期應計項目，以分析這些盈餘管理變數與會計方法選擇的關係，以及這些項目是否會影響新上市公司在上市後二年內的股票異常報酬。研究結論在理論模式方面為：（1）當投資者認為成功公司選擇淨利增加方法（直線折舊法）而失敗公司選擇淨利減少方法（加速折舊法）時，將可獲得成功公司與失敗公司皆會選擇直線折舊法的混合均衡條件，故無法揭露公司的真實型態。（2）當投資者認為成功公司會選擇加速折舊法而失敗公司會選擇直線折舊法，將可獲得成功公司選擇加速法而且失敗公司選擇直線法的分離均衡條件。在實證研究方面為：（1）新上市前後負債權益比率較高的公司，愈有可能採用能增加盈餘的折舊方法以取信社會大眾。（2）在上市當年及上市後二年內資產報酬率愈高的公司，愈不需要藉由採用使會計盈餘增加的折舊法。（3）應計項目與折舊提列方法選擇無關的原因可能是：公司欲成功上市的方法很多，例如，利用銷貨給關係企業來窗飾經營成果；或因新上市公司通常規模不大，固定資產金額不高，故管理者利用折舊提列方法操縱損益的實質效果較小，致使其較無動機利用應計項目調整來影響折舊提列方法。（4）上市後第二年的非裁決性當期與長期應計項目，乃與異常報酬有顯著相關。此表示資本市場存在者管理者所無法控制的經濟與管制因素。 This paper combines asymmetry information and signaling models to show, underdifferent bankruptcy costs, the conditions of pooling equilibrium for successful andfailed firms that choose the same depreciation method but lead to different operatingresults. We also shows the conditions of separating equilibrium, for which successfulfirms choose different depreciation method to that of failed firms. To confirm whetherthe empirical results are consistent with the theory, the paper sampled initial publicoffering (IPO) companies to examine the factors that influence the choice of accountingmethods (using depreciation methods as the example). Furthermore, the paper separateaccrual items into discretionary current, non-discretionary current, discretionarylong-term and non-discretionary long-term accrual items to analyze the relationshipbetween these variables and the choice of accounting methods.The results of analytical models are: (1) When investors perceive that successfulfirms choose earnings increasing method (straight-line deprecation method) whereasfailed firms choose earnings decreasing method (accelerate deprecation method), theyare able to obtain the conditions of hybrid equilibrium. (2) When investors perceivesuccessful firms will choose accelerate method, whereas failed firms choosestraight-line method, they can obtain the conditions of separate equilibrium. Moreover,the empirical results show: (1) The companies that have higher debt-to-equity ratiobefore IPO tend to adopt earnings increasing method to gain the trust of the investor. (2)The companies that have higher assets returns in the year and two years after IPO tendnot to adopt earnings increasing method. (3) Because there are many ways to havesuccessful IPO, the impact of using depreciation methods to manipulate earnings isminimal. It reduces their motive of utilizing accrual items adjustment to affectdepreciation method. (4) The non-discretionary current and long-term accrual items inthe second year of IPO are significantly positively related to abnormal returns.