K21 and capital rate of return, i.e "r"

Piketty:

I think that here there is some confusion in these critiques between the interest rate and the rate of return to capital. The rate of return to capital is a much broader concept than just interest rates. If the rate of return on capital were really going to zero, as Summers seems to argue, then the capital share in GDP and the capital share in the economy would be going to zero. This has not been happening at all. Right now, including five years of total crisis, the capital share is much higher than it was twenty years ago in most developed countries. 

So, what’s in the capital share? With the capital share you can have interest payment, dividends, corporate profits (with some of it going into retained earnings which feeds capital gains), and you have rental income. If you make a sum of all these forms of capital payment, then the capital share has not been going to zero at all. 

I think that it is just wrong to take the interest rate on public debt as an indicator of the rate of return. Public debt is a very particular kind of asset: it provides liquidity services – that is, you can easily sell your Treasury bonds – and that is partly why people accept having relatively low returns in comparison to other assets. Also, we are not completely out of the financial crisis yet and we have had a lot of creative monetary policies that have kept interest rates low. 

I think that where Summers is right, and this is where he wants to get, is that we have been asking too much of creative monetary policies in recent years, pretty much everywhere – in the US, in the UK, and in the Eurozone – because at the end of the day we have this very low interest rate on some assets such as public debt or certain categories of short-term or medium-term loans, but this is creating bubbles in other assets – in real estate and in some segments of the stock market – and so you have huge return on some other assets at the same time as you have zero interest rates on the public debt. So in fact, this is probably amplifying the inequality in rates of return, in this huge heterogeneity of rates of return. 

My bottom line is that the average rate of return for all assets combined is not going to zero. It has been going down a little bit over the past 20 to 30 years because of the rise in the capital-to-income ratio, but it has declined less than the increase in the capital–income ratio, so that the capital share has actually increased. My second point is that you have a huge heterogeneity in rates of return between assets, and that having very low interest rates on certain assets, such as public debt in particular, is not necessarily a good thing because it stimulates very high bubbles in capital gains and rates of return on other assets at the same time.