watchdy - I'm assuming you're using Bloomberg or something like it for quotes? But, in real life, how do you get that yield?

This very minute you can go on IBKR and buy a t-bill expiring Aug 17 and issued last week for 97.7. Using my handy dandy treasury calc (https://goodcalculators.com/treasury-bills-calculator/) that comes out to 4.72%  annualized yield to maturity.)  Is the ~25 point basis cut just because it was issued a week ago?    *sorry, new to buying bonds directly and simply relying on very stale b school knowledge of the subject.