美中貿易戰的外溢效應： 來自臺灣房地產市場的實證

Abstract

2018 年美中貿易戰引發貿易移轉效果，許多第三國因而得利，包括台灣。本研究探討該貿易轉移所引發的台灣出口擴張對於國內房地產市場的影響。本文採用 2016 至 2021 年的追蹤資料 (panel data)，並依循 Autor et al. (2013) 的方法，結合全國層級的產業出口變化與各鄉鎮的初始產業結構，建構出衡量貿易戰暴露程度指標 (shift-share measure)，使用差異中的差異法 (Difference-in-Differences) 進行分析，最後輔以工具變數法 (Instrumental Variable) 策略強化因果推論。

實證結果顯示，貿易戰顯著造成了台灣房地產市場擴張。貿易戰暴露程度較高的鄉鎮（實驗組)，相較於暴露程度較小的鄉鎮（控制組），房屋交易量相對增加 15.4%，總交易金額則增加 26.4%。作為輔助的工具變數法估計亦支持此發現：鄉鎮平均每位勞工的出口金額若增加新台幣十萬元，將分別帶動交易量與總交易金額上升7.14% 及 9.96%。然而，各種模型設定皆顯示貿易戰對平均交易價格的影響並不穩健。在傳導機制方面，本研究進一步發現貿易戰造成的出口衝擊顯著提升了受影響地區的平均薪資，並促進了新建案供給增加。此發現為前述結果提供了一個可能的解釋：所得提升雖推升了購屋需求，但供給面的彈性反應有效吸收了需求壓力，從而抑制價格上漲。兩者共同導致市場擴張主要體現在交易量，而非價格的增長。

This study examines how export growth, driven by trade diversion from the 2018 US-China trade war, affected Taiwan's domestic housing market. Employing a difference-in-differences (DID) framework with township-level panel data from 2016 to 2021, the analysis utilizes a shift-share measure based on Autor et al. (2013) to quantify local trade war exposure. An instrumental variable (IV) strategy complements the main analysis to strengthen causal identification.

The results indicate that the trade war stimulated significant expansion in the housing market. Townships with greater trade exposure experienced a 15.4% relative increase in transaction volume and a 26.4% increase in total transaction value. These findings are supported by IV estimates, which demonstrate that a NT$100,000 increase in export exposure per worker raised transaction volume by 7.14% and total transaction value by 9.96%. In contrast, effects on average transaction prices were not robustly significant across all specifications. An investigation into the transmission mechanisms reveals that the export growth simultaneously increased local wages and stimulated housing supply. The evidence suggests that income gains drove housing demand. However, an elastic supply response absorbed this pressure, mitigating significant price increases.