Here is a sentence that has cost American retirees an enormous amount of money.
"Yes, proof coins are allowed in your IRA."
It is true. That is the problem.
Because "allowed" and "advisable" are two different words, and the entire proof coin sales model lives in the gap between them.
A proof American Gold Eagle contains exactly the same amount of gold as a bullion American Gold Eagle. Same mint. Same purity. Same statutory eligibility.
It just costs dramatically more. And when you sell it, it usually fetches roughly the same as the bullion version.
That difference is not a rounding error. On a large purchase it can run into tens of thousands of dollars, permanently gone, on day one.
So let us answer the question properly, then answer the better question underneath it.