Short-term doldrums aside, the world’s corporations would seem to be in a strong position to grow as the global economy recovers. They enjoy healthy cash balances, with $3.8 trillion in cash holdings at the end of 2009, and they have access to cheap capital, with real long-term interest rates languishing near 1.5 percent. Indeed, as developing economies continue to pick up the pace of urbanization, the prognosis for companies that can tap into that growth over the next decade looks promising.

Yet all those new roads, ports, water and power systems, and other kinds of public infrastructure—and the many companies building new plants and buying machinery—may put unexpected strains on the global financial system. The McKinsey Global Institute’s (MGI) recent analysis finds that by 2030, the world’s supply of capital—that is, its willingness to save—will fall short of its demand for capital, or the desired level of investment needed to finance all those projects.¹Indeed, household saving rates have generally declined in mature economies for nearly three decades, and an aging population seems unlikely to reverse that trend. China’s efforts to rebalance its economy toward increased consumption will reduce global saving as well.