[TheCoelacanth]

If Peter Thiel had contributed the maximum possible with a mega backdoor Roth for every year of his life, that would total roughly $2 million, so Thiel has at least $4.998 billion in untaxed capital gains in his account.

If this passes, it wouldn't go back and make him pay taxes on those, but it would stop other people from replicating that trick and it would greatly reduce the amount of future untaxed capital gains he will get.