Hi,
First thing is that there can only ever be 21 000 000 BTC in circulation so it is impossible for the fed to own 25M BTC.

Secondly: It is not in the feds best interest to buy up loads of bitcoins because they have control over printing dollars so buying bitcoin would only drive up bitcoins price and rendering their ability to create dollars worthless.

And lastly, be careful if you trade cryptocurrencies against one another by watching what their worth in dollars because that can be misleading. Rather use what they are worth in bitcoin as a frame of reference.
Peace!