本研究旨在探討經理人員盈餘預測之發佈是否成為其操縱盈餘的誘因 之一。本研究推測，公司經理人員預估當期盈餘可能低於預測盈餘時，為避免造 成股價下跌或遭不滿的投資人控訴，可能採用各種操縱盈餘的方法，使盈餘增 加，以達所預測之目標。本研究以民國80年至81年有經理人員盈餘預測之上市公 司為樣本，將樣本分為兩組:操縱組與對照組。前者係指未操縱前盈餘較預測值 為低的公司，後者則為未操縱前盈餘已達預測盈餘之公司。然後探討操縱組之公 司相對於對照組而言，在裁決性應計項目『出售資產損益以及營業外損益等三種 可能的操縱工具上，是否有顯著不同。本研究實證結果顯示，操縱組公司之經理 人員會利用裁決性應計項目操縱盈餘使其增加，以達預測值，其中經由提高裁決 性應收帳款與裁決性存貨以增加盈餘的情形最為明顯。此外，操縱組公司之經理 人員亦曾透過出售較多投資，認列較多異常營業外利益，使盈餘增加。故本研究 之實證結果支持經理人員可能利用盈餘操縱，使盈餘增加以達預測盈餘之假說。

　　　　　The purpose of this study is to examine whether or not managers manipulate earnings after management earnings forecast is issued. Managers may fear the possibility of legal action by disgruntled investors and adverse security price effects, if actual earnings fall short of the forecasts. Therefore, they have an incentive to avoid a shortfall, and may take measures to more reported earningstoward the forecast. The sample in this study is divided into two groups: manipulation group and control group. Manipulation group contains firms whose earnings before manipulation are below forecast num beers, while controe group contains firms whose earnings before manipulation are equal or greater than forecast numbers. Possible manipulation tools include the discretion of accruals, the disposal of assets and the use of non-operating items. This study uses regression model, simple average model and random walk model to estimate the components of accruals - expected accounts receivable, expected inventory and expected accounts payable without manipulation. With respect to income from disposal of assets and non-operating items, the industry average is regarded as the expected amount before manipulation. The degree of manipulation is then estimated by taking the differences between actual and expected numbers. Using firms listed in Taiwan Stock Exchange between 1991 and 1992 as sample, the empirical results support the hypothesis that firms with earnings before manipulation below the forecasts have used accruals, disposition of assets and non-operating transactions to inflate earnings. In particular, it is found that "earnings-manipulation" firms tend to employ accounts receivable, inventory and income from non-operating items as income increasing manipulation tools.