大宗穀物進口價格對消費者指數之影響：COVID-19前後之比較

Abstract

2020年年初爆發全球性疫情COVID-19，致使各國停工停課，股市崩盤，而由於極端氣候的衝擊，導致全球農產品產出大幅下降，全球糧食危機仍然在持續加劇中。 台灣原物料匱乏，尤其大宗穀物黃豆、小麥以及玉米均仰賴國外進口，往往呈現大宗穀物供不應求的狀況。本文使用向量自迴歸模型（Vector Autoregression model），以探討大宗穀物黃豆、小麥以及玉米之進口價格、期貨價格與台灣消費者物價總指數（Consumer Price Index, CPI）及食物類消費者物價指數之間的關係。過去研究僅探討農產品價格與消費者物價指數之間的關係，很少有研究檢視農產品期貨價格與消費者物價指數、食物類消費者物價指數之間的關係，因此本文有關三類穀物（黃豆、小麥、玉米）之期貨價格與消費者物價指數及食物類消費者物價指數兩者之關係的研究可以補充過往文獻的不足之處。 本研究發現，黃豆、小麥以及玉米之進口價格對消費者物價指數與食物類消費者物價指數之影響方向並不一致。疫情前，基因改造黃豆和小麥之進口價格對消費者物價指數呈現正向的影響，非基因改造黃豆和玉米之進口價格則對消費者物價指數呈現相反方向的影響。黃豆與玉米之進口價格對食物類消費者物價指數呈現負向影響，小麥之進口價格則對食物類消費者物價指數呈現正向的影響。此外，黃豆、小麥以及玉米之期貨價格對消費者物價指數雖呈現負向的影響，其對食物類消費者物價指數則呈現正向的影響。在疫情後，本研究之結果則顯示黃豆、小麥以及玉米之進口價格對消費者物價指數與食物類消費者物價指數均呈現負向影響，黃豆之期貨價格對消費物價指數呈現正向的影響，其他則無改變，但對黃豆與玉米之期貨價格對食物類消費者物價指數呈現負向影響。

The outbreak of the global epidemic COVID-19 in early 2020 led to work stoppages, stock market crashes, and successive disasters, resulting in a significant decline in global agricultural production. Taiwan has a shortage of raw materials and a shortage of agricultural products, especially soybeans, wheat, and corn, which are all imported from abroad. This paper uses the Vector Autoregression model to explore the relationship between the import prices of soybean, wheat, and corn and the Consumer Price Index (CPI) and the food CPI in Taiwan. While previous studies have only examined the relationship between agricultural commodity prices and the food CPI, rarely have investigated the relationship between agricultural commodity futures prices and the CPI and the food CPI. Therefore, this paper will add the relationship between the futures prices of soybeans, wheat, and corn and the CPI and food CPI at the end. It is found that the impact of import prices of soybeans, wheat, and corn on the CPI and food CPI is inconsistent. Before COVID-19, import prices of soybean GM and wheat showed positive correlations with the CPI; import prices of soybean non-GM and corn were negatively correlated with the CPI. Import prices of wheat showed positive correlations with the food CPI, and the futures prices of soybean, wheat, and corn were negatively correlated with the food CPI. Import prices of soybeans, wheat, and corn are negatively correlated to the CPI and are now correlated to the food CPI. After COVID-19, import prices of soybeans, wheat, and corn showed negative correlations to the CPI and the food CPI, while the futures prices of soybeans are currently correlated with the CPI. In contrast, others are unchanged, but futures prices of soybeans and corn are negatively correlated with the food CPI.