Yes, it would be trivial for me to spread a few hundred thousand around a few banks so that I could be within the FDIC limit. What is not trivial is a brokerage

Yes, it would be trivial for me to spread a few hundred thousand around a few banks so that I could be within the FDIC limit. What is not trivial is a brokerage spreading around $50MM across 500+ banks. What I was trying to explain is that the people buying the T-Bills aren't individuals looking to put their money some place safe. These are large institutional investors looking to park millions (hundreds of millions?) of dollars in a safe place till they can figure out what to do.