港元兑美元走强至7.75，触及强方兑换保证水平。

Core Viewpoint - The Hong Kong dollar has strengthened against the US dollar to 7.75, reaching the strong-side convertibility guarantee level [1] Group 1 - The exchange rate movement indicates a significant appreciation of the Hong Kong dollar [1] - The strong-side convertibility guarantee level is a critical threshold for the Hong Kong Monetary Authority [1]