Demand Forecasting for Overseas Direct Sales Using the SARIMAX Model and Its Implications

Purpose - This study aims to empirically examine the applicability and effectiveness of the SARIMAX model as a quantitative forecasting tool for strategic planning in Overseas Direct Sales (ODS). By analyzing demand patterns across major markets—China, the United States, and Japan—this research seeks to identify structural differences and support the development of more refined and effective market entry and growth strategies. Design/Methodology - This study utilizes a time-series analysis based on quarterly ODS data from Q1 2014 to Q4 2024, utilizing both Python 3.11 and Stats models 0.14.0 packages. Stationarity was tested using the Augmented Dickey-Fuller (ADF) method, with logarithmic transformations and differencing applied where necessary. A SARIMAX model was employed, incorporating key macroeconomic indicators—GDP, CCI, exchange rates, and CPI—to dynamically assess their effects on ODS demand across the target markets. Findings - In China, cosmetics remain the dominant category but are projected to decline sharply in the latter half of 2025, while fashion and music maintain relative stability. The U.S. market shows modest overall growth, with a gradual decrease in cosmetics and resilience in fashion and music. Japan conserves general stability, with cosmetics retaining leadership, fashion displaying notable volatility, and music achieving steady growth. Originality/value - Practically, it offers a data-driven forecasting framework that supports SMEs and startups in formulating effective market entry and operational strategies for cross-border e-commerce. Academically, it enriches existing literature by integrating quantitative demand forecasting with international marketing strategies.