He covered exactly that (and again today on this news: https://www.bloomberg.com/opinion/articles/2023-08-02/the-us-is-more-aa-now https://www.bloomberg.com/opi

He covered exactly that (and again today on this news: https://www.bloomberg.com/opinion/articles/2023-08-02/the-us-is-more-aa-now https://www.bloomberg.com/opinion/articles/2023-08-02/the-us..., it's free by email but I think unfortunately no (legitimate/non-archive) way to find old columns for free if you weren't subscribed at the time): > When we last talked about this in May, I looked at various rules — for money market funds, for Federal Reserve collateral, for cleared derivatives margin, for bank and insurance capital — until I got bored; all of them say that Treasuries are Treasuries, that they are treated as about as risk-free as it gets, without any reference to ratings. [...] If you have that trade, please email me! If you were allowed to hold Treasuries when they were rated AAA (by Fitch), but not now that they are rated AA+ (by Fitch), I would love to hear about it. But I don’t think there are a lot of those people out there.