What a central bank actually does when it cuts rates

When a headline says a central bank "cut rates", it is describing a change to one specific number that most people never encounter directly. Understanding what that number is makes the rest of the news legible.

The rate they actually set

The policy rate is the rate at which commercial banks lend to each other overnight, or the rate the central bank pays banks on reserves held with it. Either way it is a wholesale rate between financial institutions, not a rate any household is offered.

The central bank does not order anyone to charge it. It makes that rate happen by standing ready to lend or borrow unlimited amounts at that level, which means no bank has a reason to transact away from it.

How it reaches you

Through a chain, and the chain has different speeds at each link.

• Overnight lending between banks changes immediately.
• Bank funding costs change over weeks, as deposits and wholesale borrowing reprice.
• New loan rates change over weeks to months.
• Existing fixed-rate loans do not change at all until they mature.

This is why a cut announced today does not show up in the economy today. Most estimates put the peak effect on activity somewhere between twelve and eighteen months out, which means a central bank is always acting on a forecast rather than on the present.

Why it works at all

Lower rates make borrowing cheaper, so more borrowing happens and more is spent. They lower the return on saving, which nudges money toward spending or toward riskier assets. They lift asset prices, which makes owners feel wealthier. And they usually weaken the currency, which helps exporters.

Every one of those channels is a tendency rather than a law. In some conditions, notably when confidence is very weak, cutting rates achieves remarkably little. Japan spent a long time demonstrating this.

What to take away

When you read that rates were cut, the useful questions are: by how much relative to expectations, what did they say about the next move, and what does the bond market think happens over the following year. The bond market answer is usually the most informative of the three.

This is general education and not investment advice.