Copper prices fluctuated sharply during the reporting period (August 17-21). On the macro front, the U.S. Treasury's announcement of expanded buybacks of long-term bonds pulled Treasury yields lower, and the market sees the operation of supporting buybacks through new debt issuance as essentially injecting dollar liquidity into the market. Meanwhile, although FOMC minutes showed some Fed officials supported rate hikes, the market widely expects no further hike before December. As a result, the USD index fell below 99, offering support to copper prices. Fundamentally, low deliverable LME copper inventory caused LME copper prices to rise sharply last Monday, also lifting China's copper prices. However, as LME inventory subsequently increased and market sentiment eased, copper prices gradually retreated.