Further we find that children with parents in the top 10% and even more in the top 1% (red upper corner in heat map) have considerably higher degress of homogamy than the rest of the population. If you think about intergenerational capital reproduction this really matters

here you can see what is the average parental wealth percentile of men women in each percentile marry (sounds technical).
But what you can notice is that the relationship gets steeper in later times, indicating again that homogamy by parental wealth is increasing over time

a technical note!
The way wealth is normally calculated is: assets-liabilities.

We believe that using only assets is probably a better indicator of social status. Correlations get stronger and weird effects at the bottom of the distributions disappear (see graphs).

the intuition here is that people with the capacity to seriously indebt themselves are not that bad off in many ways. But this is a point to be made more in-depth in another paper.