本研究目的在探討上市後業績與盈餘衰退之公司其強制性財務預測的準確性、修正頻率與時間特性等資訊特質是否與非衰退公司之間有顯著的不同。

本研究所選取之樣本期間自民國80年6月至民國85年底之新上市公司曾在上市當年度及上市後三年之內公告或更新財務預測與盈餘等相關資訊者，總計樣本共計152家，341個觀察值。研究方法以迴歸分析為主。而研究結果如下：

1、新上市公司於申報公告強制性財務預測時常有過度樂觀的情形出現，且此一情形頗為嚴重。

2、初次上市公司於編製強制性預測時過度樂觀者，其上市之後由於經營效率（資產週轉率）及經營效果（獲利率）的降低，致使部份盈餘與業績呈現出衰退的情況。

3、初次上市公司於編製強制性預測時樂觀程度愈大者，上市之後其財務預測的誤差值越大。

4、初次上市公司於編製強制性預測時樂觀程度愈大者，上市之後其財務預測值的誤差值越大，因而必需要更新預測一次以上。

5、強制性預測的樂觀程度越大者，上市之後其業績衰退的程度並不一定較大，因為盈餘與業績變數之中有部份於上市之後是呈現成長的情況。

6、強制性預測的樂觀程度較大，且上市之後其業績的衰退程度也較大的公司，其財務預測的更新頻率相對較高。

7、上市前後強制性預測過度樂觀且上市後業績衰退的公司，其修正財務預測的時間會刻意的延後，而大多集中在半年報公告前後、年底及年報公告之前，且有集中於第四季的情況。

This study aims to examine the relationship between the revision of mandatory forecasts and the changes in operating performance. This study contends that the forecast revisions should significantly correlate with changes in operating performance. No such study has investigated this issue in the past literature; thus, this is an important issue. This study selects samples from the period between June 30, 1991 and December 31,1996.

The empirical findings of this study can be summarized as follows:

1. The mandatory forecasts of IPO(lnitial Public Offering) companies are usually optimistic.

2. The volatility of operating performance comes from the declining of operating efficiency or effectiveness.

3. The more optimistic the IPO companies are the more percentage they need to revise the forecasts.

4. Some variables of operating performance grow up after IPO.

5. The more optimistic the forecasts are the higher the frequency of the revision of forecasts.

6. The revision of forecasts falls mostly on the mid year ,the year end and the fourth season of the year.