Thanks for answering my questions!

I can't agree more with your last sentence. Why Blackrock? I really want to read their reasoning of using Blackrock as a broker other than it being the biggest fund manager. The Fed is big enough and why can't it buy the bonds directly. Maybe their weak excuse is that they can execute it via Blackrock ETFs quickly. But still...then why not spread it evenly over other institutions like Vanguard, Fidelity, etc.?