What is Central bank?

A central bank is the public institution that manages the money of a country or region. Well-known examples are the Federal Reserve in the United States, the European Central Bank for the euro area and the Bank of England in the UK. Its main lever is the policy rate, the interest rate at which it lends to or pays commercial banks. That rate filters through to mortgages, savings accounts, business loans and government bonds. Most central banks are tasked with keeping inflation, the general rise in prices, low and stable. Some, like the Federal Reserve, also aim to support employment.

When inflation runs high, a central bank usually raises its policy rate. Borrowing becomes more expensive and saving more rewarding, which tends to cool spending and price rises. When the economy weakens, it usually cuts the rate to encourage borrowing and investment. It can also buy government bonds in large quantities, known as quantitative easing, to push longer-term interest rates down.

A hypothetical example shows why investors watch these decisions. Say you hold $10,000 in a bond fund with a duration of 8. Duration is a measure of how sensitive a bond's price is to interest rates: roughly, the price moves by the duration in percent for each one percentage point change in yields, in the opposite direction. If rate rises push yields up by 2 percentage points, the fund falls by about 8 × 2 = 16%, or $1,600, leaving about $8,400. Meanwhile, $10,000 in a savings account paying 1% that rises to 3% would now earn $300 a year instead of $100.

A common misunderstanding is that central banks control all interest rates and steer markets directly. They set short-term rates, but longer-term bond yields are set by buyers and sellers in the market. Prices often move on expectations well before a decision is announced, and the effects on the economy arrive with a delay. In 2022, US inflation reached about 9% and long-term Treasuries lost about 30% as rates rose sharply, a reminder that bonds are not immune to policy shifts.

For a private investor building a long-term portfolio, central bank policy shapes the return on cash, the value of bonds and the price investors are willing to pay for shares. It also affects how stocks and bonds move together, which matters for diversification. Understanding what central banks do helps investors read the news calmly rather than react to each announcement.

By Dr. Harry Hamann

What does a central bank do?
It sets the key short-term interest rate, manages the money supply and oversees the banking system. Its main goal is usually stable, low inflation, and some central banks also aim to support employment.

How do interest rate rises affect stocks and bonds?
Higher rates lower the price of existing bonds, because new bonds pay more. They can also weigh on share prices by raising borrowing costs and making cash more attractive. The size of the effect varies and markets often react to expectations before decisions.

Is a central bank part of the government?
Central banks are public institutions created by law, but most are designed to operate independently of day-to-day politics, so that interest rate decisions focus on inflation and economic stability rather than election cycles.

What is the difference between a central bank and a commercial bank?
Commercial banks take deposits and lend to households and businesses. A central bank is the bank for those banks: it lends to them, holds their reserves and sets the policy rate that influences the rates they charge customers.