本研究以2025年美國對等關稅政策為研究背景，探討其對臺灣出口之影響，並檢驗是否存在由美國轉向墨西哥之出口轉單現象。本文使用財政部關務署2025年出口資料，建構包含國家、產品及月份固定效果之迴歸模型，並依序由整體產品層級、第十六類產品（P16）及HS6層級產品進行分析，以辨識出口調整之來源與特徵。 實證結果顯示，在整體產品層級下，美國出口於各月份均維持顯著正向效果，而墨西哥則多呈顯著負向效果，顯示對等關稅政策並未引發全面性之出口轉單。然而，當分析聚焦於P16產品時，墨西哥出口於九月至十月期間轉為顯著正向，顯示出口調整主要集中於特定產品類別，且具有時間遞延特性。進一步於HS6層級分析發現，847180「其他自動資料處理機單元」產品之出口趨勢與P16整體表現最為接近，且於交乘模型與子樣本分析中均呈現顯著之墨西哥出口擴張效果，顯示其為P16出口重新配置之主要驅動產品。 此外，補充分析發現，工具機產業主要透過提前出貨調整出口時點以因應政策變動，而半導體產業則因深度嵌入全球價值鏈，其出口流向更多反映供應鏈分工而非最終市場需求。整體而言，本文認為美國對等關稅政策所引發之出口調整並非全面性市場重新分配，而是呈現產品集中性、時間遞延性及產業異質性等特徵。;This study investigates the impact of the United States′ Reciprocal Tariff Policy implemented in 2025 on Taiwan’s export performance and examines whether the policy induced trade diversion from the U.S. market to Mexico. Using Taiwan Customs export data for 2025， this study employs regression models with country， product， and month fixed effects. The analysis proceeds from the aggregate product level to HS2 Product Category 16 (P16) and further to the HS6 product level to identify the source and characteristics of export adjustments. The empirical results show that， at the aggregate level， exports to the United States remained significantly positive across all months， while exports to Mexico were generally significantly negative， suggesting that the reciprocal tariff policy did not generate a broad-based trade diversion effect. However， when the analysis focuses on P16 products， exports to Mexico became significantly positive during September and October， indicating that export adjustments were concentrated in specific product categories and exhibited a lagged response to policy changes. Further analysis at the HS6 level reveals that product 847180 exhibited export patterns most consistent with those of P16. Both the interaction model and the subsample analysis show significant export expansion to Mexico， suggesting that product 847180 was the primary driver of the observed export reallocation within P16. In addition， supplementary analyses of the machine tool and semiconductor industries reveal heterogeneous responses to the tariff policy. The machine tool industry primarily responded through shipment timing adjustments， such as front-loading exports， whereas the semiconductor industry’s export patterns were largely shaped by global value chain specialization rather than final market demand. Overall， the findings suggest that the effects of the U.S. reciprocal tariff policy were characterized by product concentration， time lag， and industry heterogeneity， rather than a comprehensive reallocation of export markets.
