The OLIGRACH Act specifically establishes four tax brackets:

· 2% for all wealth between 1,000 and 10,000 times median household wealth;

· 4% for all wealth between 10,000 and 100,000 times median household wealth;

· 6% for all wealth between 100,000 and 1,000,000 times median household wealth;

· 8% for all wealth over 1,000,000 times median household wealth

For reference, current median household wealth is around $120k: https://dqydj.com/average-median-top-net-worth-percentiles/

So a the current rate would be

· 2% for all wealth between $120 million and $1.2 billion

· 4% for all wealth between $1.2 billion and $12 billion

· 6% for all wealth between $12 billion and $120 billion

· 8% for all wealth over $120 billion

That top tax rate would apply to only two people, Bill Gates and Elon Musk, with a few more just barely below the $120 billion line: https://en.wikipedia.org/wiki/List_of_wealthiest_Americans_by_net_worth