US real assets are increasingly the only major game in town. Investors with global reach looking for security and return have few options as attractive, and none on the same scale. The world could soon see the kind of cash flow to the US that underpinned the late-1990s stock market boom, culminating in the tech bubble.

Too much saving means too much investment for the world as a whole: no export surplus can serve as a safety valve, as it can for individual countries.

World savings were just under a quarter of gross world product last year, matching 2007’s record high ratio. But in 2007 the world’s baseline real interest rate – the inflation-adjusted yield of US 10-year Treasuries – was just under its long-run average of about 2.5 per cent. By 2012, the real 10-year Treasury yield was minus 0.5 per cent.