Impacts of China’s Temporary Storage Policy on Corn Market Integration

China’s temporary storage policy (TSP) for corn provides a useful setting for examining how price-support policy is associated with domestic-global market integration. Using weekly Dalian Commodity Exchange (DCE) and Chicago Board of Trade (CBOT) corn futures prices from 2007 to 2019, this paper combines two-break LM unit-root tests, regime-specific Johansen cointegration tests, and confounder-adjusted monthly error-correction models. The structural-break analysis identifies price-regime changes around April 2013 and July 2015. The Johansen results show no stable long-run relationship between Chinese and global corn prices during the early TSP and widening price-gap periods, whereas one cointegrating relationship emerges around the market-oriented reform period. Additional specifications using alternative price-gap measures and monthly controls for imports, substitute imports, inventories, oil prices, exchange rates, and futures-market liquidity support this pattern. Mechanism evidence indicates that wider domestic-global price gaps were associated with faster growth in corn-substitute imports. The findings suggest that administered procurement prices and stockholding were associated with weaker long-run price transmission, while the transition toward market-oriented purchases and producer subsidies was associated with stronger domestic-global price linkage.