Kojima Hisashi

This study uses the International Input-Output Table to estimate the impact on Japan of China's ban on the import of waste plastics implemented at the end of 2017. Initially, by employing an econometric model, it was estimated that Japan's total waste plastic emissions decreased by an average of 39,000 tons from 2018 to 2022 due to China's ban on waste plastic imports. This reduction corresponds to 0.46% of the average annual total waste plastic emissions. Assuming a proportional relationship between Japan's total waste plastic emissions and domestic production, it was projected that the domestic production would decrease by an average of 0.46% annually. Furthermore, due to the anticipated decrease in Japan's production leading to a reduction in the import of intermediate goods from China and other countries, the study used the modified Leontief inverse matrix derived from the International Input-Output Table to calculate the negative economic multiplier effects （decrease in production） on China and other countries resulting from the decrease in Japan's production. As a result, we showed that, on average, from 2018 to 2022, China's ban on waste plastic imports had a negative economic multiplier effect of 4.2 trillion yen in Japan, 119.5 billion yen in China, and 5.0 trillion yen in the world.

資産価格はしばしばファンダメンタル・バリューから乖離し，時として金融市場は資産価格の大きな下落や変動に見舞われる．急激な資産価格変動を緩和するための措置として，多くの国々で空売り規制が導入されてきた．本稿は空売り規制の導入が資産価格に与える影響を分析する．私的情報や価格支配力を持つ投資家と私的情報を持たない価格受容的な投資家が混在する資産市場を想定する．空売り規制の導入が事前に予期されていない場合，空売り規制が資産価格をファンダメンタル・バリューから乖離させることが明らかになった．これは資産価格の変動を大きくすることにもつながる．とりわけ資産価格の下支えが望まれるような下落相場の状況では，空売り規制の導入はより一層の価格下落をもたらすことになる．