A question that comes up at CT quite a bit is: who has benefited from the massive increase in US income inequality over recent decades. I finally got around to chasing down Congressional Budget Office data (derived from tax records for the period 1979 to 2005), and the answer, in short is:

• The top 1 per cent roughly doubled their share of both pre-tax income (9 per cent to 18 percent) and after-tax income (7.5 per cent to 15 per cent)
• The rest of the top 10 per cent slightly increased their share (from about 20 to about 22 per cent)
• The next 10 per cent held their share (about 15 percent)
• The remaining 80 per cent of households saw their share drop (from 58 per cent to 48 per cent of post-tax income, with the biggest drops coming at the bottom. The bottom 40 per cent of households now get a smaller share of post tax income (14 per cent, down from 19) than the top 1 per cent.
  
  A couple of observations on this.

First, to answer the question “who gained from the inequality boom” we need a counterfactual. If, as is commonly claimed, pro-rich policies raised the average rate of growth of income, people in the top 20 per cent of the income distribution were better off, since they had a constant share of a bigger cake. The effects are ambiguous for everyone else, and, on any plausible numbers, everyone below the median is worse off than they would have been with moderately slower, but equitably distributed growth. On the other hand, if pro-rich policies contributed to the slowdown in economic growth for the period since the 1970s, compared to the postwar boom, then the only net beneficiaries are those in the top 1 per cent of the income distribution.

Second, the picture would probably change a bit if benefits (particularly employment-related health benefits) were taken into account. My guess is that this would probably improve the outcome for the top quintile (since this group mostly held on to benefits which increased faster than wages) and worsen it for those below the median (who have lost access to benefits over time).

Finally, it’s striking that, on the CBO figures, the tax system is almost exactly proportional: that is, it has no net redistributive effect at all. The top 1 per cent have a somewhat smaller share of post-tax income than of (measured) pre-tax income, but that almost certainly reflects their capacity to hide income from the tax system.