According to Ajay Kapur, the Citigroup strategist, the rich are responsible for the low savings rates in the Anglo-Saxon economies and the resulting global imbalances.

Kapur argues that the US, UK and Canada have developed into “plutonomies”, economies powered by the wealthy. In contrast, Japan and most of Europe are more egalitarian. In a plutonomy, there is little sense in talking about the “average consumer”; the top 1 per cent of US households account for 20 per cent of income, almost as much as the bottom 60 per cent of households put together.

The income share of the wealthy has risen dramatically in the US, UK and Canada since the 1970s. Kapur argues that technology changes, financial innovation, capitalism-friendly governments and easier immigration have all favoured the well-off.

The rise in the income share of the well-off has been accompanied by a boom in asset markets. The rich decided to consume part of those gains or, looked at another way, they saved less of their income. The savings rate of the top 20 per cent of US households fell from 8 per cent in 1992 to minus 2 per cent (they were spending more than their income) in 2000. Because of their huge share in the overall economy, this process drove down the savings rate.

Kapur has found that, over history, there has been a strong negative correlation between the share of US income of the top 1 per cent and the overall savings rate; the higher the share, the lower the rate. Economies with low savings rates tend to have current account deficits. The sustainability of these deficits, argues Kapur, thus depends on the willingness of the rich to keep spending