> How would you describe the situation when you purchase a treasury bill then?
Your cash (i.e., money) goes to the seller of the treasury bill.
If the seller is a private investor, your cash goes to the private investor (e.g., a mutual fund, a pension plan, an individual).
If the seller is the US Treasury (i.e., you bought a newly issued treasury bill), your cash goes to the US Treasury, which will deposit it, and later on, will use it to pay for the federal government's expenses, including bond interest. (Recall that, unlike the Fed, the Treasury cannot issue newly created money. The Treasury must borrow or collect taxes from the private sector to fund federal spending.)
If the seller is the Fed (through one of its primary dealers, acting as an intermediary), the trade is quantitative tightening.
>> Recall that, unlike the Fed, the Treasury cannot issue newly created money
This is where it begins to unravel and fall apart. What you say is true in theory only, it’s not true in practice:
The fed finances the primary dealer banks that participate in treasuries auctions - it accepts treasuries as collateral for repos.
The primary dealer banks are obligated to stand ready to purchase treasuries and the Federal Reserve ensures there are sufficient reserves to do so by supplying them through temporary repos (a matched purchase of Treasury debt with a requirement that the seller must repurchase later). While the Federal Reserve is not in that case directly buying the new issue directly from the Treasury, it uses the open market purchase to buy an existing bond in order to provide reserves needed for a private bank to buy the new security. The end result is exactly the same as if the central bank had bought directly from the Treasury.
Your cash (i.e., money) goes to the seller of the treasury bill.
If the seller is a private investor, your cash goes to the private investor (e.g., a mutual fund, a pension plan, an individual).
If the seller is the US Treasury (i.e., you bought a newly issued treasury bill), your cash goes to the US Treasury, which will deposit it, and later on, will use it to pay for the federal government's expenses, including bond interest. (Recall that, unlike the Fed, the Treasury cannot issue newly created money. The Treasury must borrow or collect taxes from the private sector to fund federal spending.)
If the seller is the Fed (through one of its primary dealers, acting as an intermediary), the trade is quantitative tightening.