[mym1990]

Not really the source and not specific to the bottom 25(but the bottom 50), based on this graph(https://fred.stlouisfed.org/series/WFRBLB50107) we can see net worth going up quite dramatically. If you look at pretty much any metric of capital(https://fred.stlouisfed.org/release/tables?rid=453&eid=81366...), it has been rising for the bottom 50. How much of that is attributed to income vs government stimulus is unclear.

[bcrosby95]

That chart basically mirrors real estate prices.