From the blog of Michael Pettis (the link to the full post is highlighted):
Does cutting taxes on the wealthy lead to greater growth?
“Policies that increase income inequality can in some cases lead to higher savings, higher investment, and greater long-term growth. But, in other cases, such policies either reduce growth and increase unemployment or force up the debt burden. What determines which of these outcomes takes place is whether or not savings are scarce and have constrained investment.”
To give you a better idea of the argument, here is his conclusion. Pettis’ post may debunk the shibboleths of both left and right, while providing scope for reconciliation:
“Trickle-down economics does indeed work, as does its opposite, trickle-up economics, depending on underlying conditions that are not hard to specify. The key is the relationship between desired investment and actual investment. When the former exceeds the latter, policies that increase income inequality will generally cause savings to rise and expenditures to shift from consumption to investment; this leads to higher future growth that will eventually more than compensate ordinary and poor households for the increase in income inequality.
When desired investment is broadly in line with actual investment, however, there is no trickle-down effect. Policies that increase income inequality must permanently lower growth in the long run, although, in the short run, lower growth can be postponed by an increase in the debt burden.
In advanced economies, like those of the United States and Europe, there is no savings constraint on desired investment, so income inequality can only result in higher debt or higher unemployment and slower growth. It is only in developing countries that income inequality may boost growth, although in countries that have pursued the Gerschenkron model of forcing up domestic savings, like China has, actual investment can substantially exceed desired investment. This makes the reduction of income inequality or the channeling of wealth from the state to ordinary and poor households an urgent matter.”