This study analyzed the impact of new move-ins of 1,000 units or more on the Jeonse prices of nearby existing complexes in the Seoul apartment market from July 2011 to December 2025. To this end, a stacked difference-in-differences method, which accounts for differences in treatment timing across individual move-in events, was applied. The results showed that new move-ins acted as localized supply shocks, lowering nearby Jeonse prices, and the effect varied depending on the supply-and-demand conditions of the Jeonse market. This suggests that the price effect of housing supply manifests in combination with market conditions rather than in an average and linear manner. The academic contribution of this study lies in identifying the price effect of move-in events at the event level and demonstrating that the effect of housing supply on Jeonse prices is heterogeneous, depending on market supply-and-demand conditions. From a policy perspective, this also implies that the effect of supply expansion is not determined solely by the supply volume, and that the timing of supply and regional supply-and-demand conditions must be considered together.
Seongwon Lee (Wed,) studied this question.