Do returns to wealth vary widely across households and rise with wealth?
Core argument: Twenty years of Norwegian tax data show a 180 basis point gap in median returns to wealth between the 10th and 90th wealth percentiles, with average returns on overall wealth of 3.7% and a standard deviation of 6.1%.
Analyzing 20 years of Norwegian tax data reveals significant heterogeneity in individual returns to wealth, with a 180 basis point difference in median returns between the 10th and 90th wealth percentiles. This disparity is not solely due to differences in asset allocation between risky and safe investments, as returns remain heterogeneous even within asset classes. Returns are positively correlated with wealth, and this correlation is largely driven by individuals with permanently higher returns being wealthier. For those below the 95th percentile, this correlation is mainly due to fixed effects, while for those above, it reflects compensation for higher risk exposure. The average return on overall wealth is 3.7%, with a standard deviation of 6.1%, indicating substantial variation across households.


Ed Comment: I’m very skeptical of the conclusions. My experience is that almost all excess return comes from hidden (unaccounted-for) risks. For example, how do they account for liquidity risk, which probably adds 300 basis points of return for a given level of beta (correlation) risk (i.e. private equity outperforms public equity by 300 basis points for a given correlation with the market. My guess is that they don’t measure liquidity risk but that rich investors carry more illiquid assets to capture the 300 points (I do). Another example is duration risk. My guess is they don’t measure it. So I think more than showing the rich are savvy investors, it really just shows they are taking more risk, no surprise.
These are the second and third papers cited to support the proposition that the rich get higher returns. They overlap, but I found the data compelling. Both are using Norwegian data which documents both capital income and actual individual wealth stock, they looked at 1993-2013 so through two business cycles.