遞延所得稅資產備抵評價是否具有損益平穩化與資訊傳遞效果？

Does the Valuation Allowance of Deferred Tax Assets Have the Dual Effects of Income Smoothing and Information Signaling？

過去文獻對損益平穩化之研究多著重於裁決性應計項目之操縱，僅少數文獻針對特定會計科目或產業進行探討。過去文獻也指出遞延所得稅資產備抵評價（簡稱DTA備抵評價）能夠傳遞資訊內涵給投資人，管理當局也能夠透過備抵評價所擁有的會計裁量權進行盈餘管理。本文以一般性產業DTA備抵評價作為盈餘管理工具，檢視其是否具有預期損益平穩化、當期損益平穩化及訊息傳遞效果，並進一步實證其損益平穩化及訊息傳遞效果是否共同存在（co-existing），可分別傳達不同訊息給市場投資人。實證結果發現：（1）在「工作安全動機」下，裁決性DTA備抵評價具有預期損益平穩化效果。（2）在「風險分散動機」下，有當期損益平穩化動機存在之公司，其DTA備抵評價具有當期損益平穩化效果，而且盈餘波動性高的公司比盈餘波動性低的公司，更有動機採用DTA備抵評價來進行損益平穩化。（3）在「資訊不對稱動機」下，當公司價值低估時，DTA備抵評價具有訊息傳遞效果；但當公司價值高估或公平表達時，DTA備抵評價不具訊息傳遞效果。（4）在進行相關動機聯合檢定時，當公司價值被市場低估，且當期盈餘波動性高時，管理當局有強烈動機同時進行損益平穩化及訊息傳遞之盈餘管理行為。但當「當期損益平穩化」動機存在，「訊息傳遞」動機不存在時，實證結果並不顯著，此種結論與Kanagaretnam et al.（2004）以金融業「裁決性貸款損失準備」科目所得出的結論並不一致，可能原因是會計科目本身性質及會計準則公報對操縱工具規範程度不同所致。 Prior documents had paid much attention to detect income smoothing in discretionaryaccrual items, but only little research was emphasized to detect earning management byusing special account or a more homogeneous sample. Prior studies also indicate thatdisclosures of changes in valuation allowance of deferred tax assets can conveyinformation contents to investors. Managers can also use the discretion available in settingvaluation allowance to manage reported earnings. Our paper uses the valuation allowanceof DTA as a tool of earnings management and exploits a broader sample to examinewhether valuation allowance of DTA can be exercised to anticipatory income smoothing,current income smoothing and information signaling. Moreover, we also further examinewhether income smoothing and signaling are co-existing and convey different informationto investors.Empirical results indicate that ：(1) Under job-security incentive, discretionaryvaluation allowance of DTA can be exercised to achieve anticipatory income smoothing.(2) Under risk-shared incentive, the firm with current income smoothing incentive couldexercise the valueation allowance of DTA to realize current income smoothing. And thefirm with high earnings volatility has stronger incentive to exercise income-smoothing byusing the valuation allowance of DTA than the firm with low earnings volatility. (3)Uunder information-asymmetry incentive, when the firm is undervalued, its valuationallowance of DTA has the signaling effect, but when the firm is overvalued or fair-valued,the signaling effect cannot be found. (4) In examining the joint test, when the firm is undervalued and has higher earnings volatility, managers have stronger incentive tosimultaneously execcise income smoothing and signaling. But when the firm has thecurrent income smoothing incentive rather than signaling incentive, co-existing effectscannot be found. Such results are not the same as those of Kanagaretnam et al. (2004).Possible reasons are that discretionary loan loss provision and valueation allowance ofDTA are different in account nature regulation of managerial discretion of GAAP.