This incident occurred in 2018. The user opened an unusually large BTC long position within a short period using high leverage. Despite multiple 'reduce position requests' issued by the platform based on risk control measures, the user refused to cooperate, significantly impacting market stability. In accordance with the user agreement, the relevant account was frozen. Subsequently, due to the high leverage ratio and the decline in BTC price, the position was eventually liquidated. If this market manipulation behavior had not been stopped in time, it would have caused a massive shock to all trading users. During this incident, the platform injected 2,500 BTC from its own funds into the risk reserve pool to minimize the impact on other users. Since then, the platform has continuously optimized its risk control system through mechanisms such as mark price and position limits. As a centralized exchange, we bear the responsibility of trust and operational accountability, and therefore have the obligation to protect users engaged in normal trading. Event announcement: https://www.(okx.com)/zh-hans/help/announcement-on-the-investigation-and-handling-of-btc-contract-abnormality-warehouse-crossing-receipt