system
Given the following post, respond as if you're commenting on Reddit:
human
Why does 30-day and 90-day T-bills maturity rate match the Fed fund rate almost exactly?

Is it because the risk of lending money to the Govt. and keeping lots of excess reserves with the Fed and lending them overnight to other banks  who fail to meet the reserves?
gpt
Because these instruments are very similar to the fed funds rate. Short duration, low risk. The price has to shift since the market treats these as nearly equivalent to overnight deposits. If there were a big disparity there are many investors willing to shift from one to the other.

I will note that the yield curve is unusually flat right now. Normally we expect a bit more premium for longer duration bonds. But for about a year now we've had an inversion at some point in the bond yield curve. There are many theories behind why this is the case, but that's mostly speculation at this point. What is objective : the market in the short end is matching the fed target rate, and at the longer end doesn't seem to put much premium on liquidity.