Why does QE tend to push long-term interest rates down?

Its bond buying lifts prices, lowering yields

Printing money | TradeLiga

Central banks can do something nobody else can: create money. In a crisis, they sometimes create a lot of it.
With quantitative easing (QE), a central bank creates new money to buy bonds from banks and investors. That pushes long-term interest rates down and floods markets with cash.
Real example: the Fed used QE after 2008 and again in 2020. Its balance sheet grew from under US$1 trillion in 2007 to about US$9 trillion in 2022. Bank Indonesia also bought government bonds directly in 2020.
But money is a claim on goods. If money grows much faster than what there is to buy, prices rise. QE, huge government spending and supply shocks helped push inflation up in 2021–22.
Push it too far and you get hyperinflation. Zimbabwe ended up printing a 100-trillion-dollar note; in Venezuela in 2018, prices rose by tens of thousands of percent.
Common mistake
Mistake: “printing money always means instant hyperinflation.” After 2008, years of QE came with low inflation. What matters is how much, for how long, and whether the economy can produce more.
Key takeaway
QE means creating money to buy bonds. A crisis tool that can help, or fuel inflation if overused. That's one reason central banks are kept independent.

Quantitative easing means a central bank... Creates money to buy bondsThe new money buys bonds, which lowers long-term rates and adds cash to the system.
Too much money printing can cause... HyperinflationWhen money grows far faster than goods, each unit of money buys less and less.
Why does QE tend to push long-term interest rates down? Its bond buying lifts prices, lowering yieldsBond prices and yields move in opposite directions, so a big buyer pushes yields down.
After 2008, years of QE came with... Low inflation for a long timeWeak demand after the crisis meant the extra money didn't push prices up much.