Because nobody else wants it.
Holdings by foreign central banks, over the last one year, were a net decrease. A net sell-off.
Meanwhile, Treasuries spike, as this is the preferred ‘safe haven.’
So in case you were wondering ‘who funded the housing bubble?’ there is the answer.
Chart above plainly tells the story: red line tracks foreign purchases of agency (FNM and FRE) debt (notice how it ends below zero); yellow line reflects the humongous recent increase in the purchase of Treasuries. To the moon Alice! TO THE MOON!
It is neither “Federal” nor “Reserve.”