Although, still room for losses with those numbers ($50B) https://ycharts.com/indicators/3_month_t_bill, and make them more likely to want to hold to maturity.
But not because rates do not change (they do, a lot: for example 3-month rate jumped by over 0.5% in 2 weeks of Oct 2022). But due to the short duration such change barely affects the remaining interest paid by each bill, which is what determines bill's price.
