調配機制對毛猪價格波動性之影響

The Impact of Deployment Mechanism on the Volatility of Hog Price

毛猪供銷業務與調配會議的召開，一直以來是行政院農業委員會穩定國內毛猪價格的一個重要管道。本研究利用GARCH、EGARCH 與GJR-GARCH 三個模型，檢視藉由事先管控各肉品市場次月的毛猪供應數量，穩定毛猪價格波動的成效。研究結果顯示，整體而言，受限於肉品市場的配合意願，加上調配會議管控數量的方式，可能讓各肉品市場對於需求變動的因應能力下降，造成此一政策整體效果有限。不過，進一步分別檢視國內八個主要肉品市場後，雖然每個月前二十天，政策成效仍屬有限，但隨時間經過，加上月底調配會議召開與檢討，則是可以發現政策的部分成效，多數市場毛猪價格有波動減小的現象。另外，實證結果發現國內毛猪價格的波動確實存在不對稱性，當非預期訊息造成實際價格低於預期價格時，引起的毛猪價格波動較小。

The convention of hog business and deployment mechanism has beenplayed as a critical channel to stabilize Taiwanese hog price. In this paper,GARCH, EGARCH, and GJR-GARCH models are applied to examine thestabilization policy on hog price volatility, by ex-ante negotiating the supplyquantity of hog for each local market in next month. According to theempirical results, the effects of the policy are limited by the willingness ofeach local hog market to this policy. In addition, the method of deploymentmechanism in the convention is another factor to reduce their flexibility whenthe demand is changed. However, some new information may be found bylooking at the effects in the eight main markets individually. The resultsshow that the policy effect in the first twenty trading days is limited. When itapproaches to the end of the month and the convention of deploymentmechanism is hold, we can find that the policy works partially. The hogprice volatility is reduced by the deployment mechanism in most local hogmarkets. Further, the empirical evidence also shows that the volatility ofTaiwanese hog prices is asymmetric. When the realized price is lower thanexpected price caused by those unexpected information, the hog pricevolatility is smaller.