Expanding a program already in place in New York City and Miami, the US Treasury will be requiring full purchaser information on all cash real-estate transactions.
It’s called Geographic Targeting Orders (GTOs), and it has been expanded to include Boston; Chicago; Dallas-Fort Worth; Honolulu; Las Vegas; Los Angeles; Miami; New York City; San Antonio; San Diego; San Francisco; and Seattle (US Treasury link).
I do not know how much real estate in these areas is criminals and despots trying to conceal their ill gotten gains, but my guess is that, at least at the high end, it is quite a lot.
Assuming that the GTO regime is relatively strict, and given the vicissitudes of the Treasury, and the fact that the current President almost certainly laundered money for Russian oligarchs, I have my doubts.