China’s foreign-exchange reserves rose $19.55 billion in August to $3.438 trillion, according to data released Monday by the People’s Bank of China. The total exceeded the $3.425 trillion forecast cited in a Wall Street Journal economist survey and the $3.425 trillion median forecast in a Reuters poll. Reserves stood at $3.419 trillion in July. The increase came as the yuan gained 0.49% against the dollar, while the dollar weakened 0.4% against a basket of major currencies, and as China recorded a surging trade surplus. The combination of stronger external balances and a weaker dollar renewed concerns about upward pressure on the yuan.