Donald Trump, US president, is to meet Xi Jinping, his Chinese counterpart, at Mar-a-Lago in Florida this week. Discussions of economics seem likely to focus on China’s trade and exchange rate policies. This would be a mistake even if the US president’s views of trade were not mistakenly fixated on bilateral imbalances. Far more challenging and important is integrating China into the financial system. US policymakers should worry about China’s capital account, not its current account. That is where danger now lies.

Why does the capital account matter more? The answer is that this is where two interrelated aspects of an economy interact with the world economy: macroeconomic balances between savings and investment; and the financial system. In both respects, the Chinese economy is, to cite the celebrated words of former premier Wen Jiabao, “unstable, unbalanced, uncoordinated and unsustainable”. That was true in 2007, when he said it. It is truer today. As the Chinese authorities realise, but their western counterparts may not, the integration of China’s financial system into the global economy is fraught with peril.

Consider a few facts. Annual gross savings in the Chinese economy amount to 75 per cent of the sum of US and EU savings, at over $5tn last year. China’s gross investment, at 43 per cent of gross domestic product in 2015, was still above its share in 2008, even though the economy’s rate of growth had fallen by at least a third. To sustain such high investment, the ratio of credit to GDP soared from 141 per cent of GDP at the end of 2008 to 260 per cent at the end of last year. The “shadow banking system”, in the form of “wealth management products” and other instruments, has exploded. Interbank lending has also soared. Last, but not least, the banking system is now the world’s largest.