The results from the just reported 4 week bill auction reveals a yield of 0.000% and that is not a misprint. The auction last week yielded .04%. Year end parking of money in a safe place is likely the main focus on the part of buyers rather than any return on that money.
Why would you buy this over cash?
Because you think its going higher — and the yield is going negative.
Its the greater fool trade . . . .