How Banks Make Money

🏦 The Business Behind Your Bank Account

A bank can feel like a safe place that simply holds your money, but it is a business, and understanding how it earns helps you use it well. Most of a typical bank profit comes from a simple idea: it pays you a low rate to hold your deposits, lends that money out at a higher rate, and keeps the difference. On top of that sit fees and a range of other services. Knowing this makes the rates and fees you see make a lot more sense.

                Key Point: The main way a bank makes money is the gap between the interest it charges borrowers and the interest it pays savers. This gap is called the net interest margin. Fees are a second source. Because lending is the engine, the rates on your savings and your loans are two sides of the same business.
            

Money In, Money Out

Deposits: the money you and others keep in accounts. The bank pays interest on some of it.
Loans: mortgages, personal loans, business loans, and credit cards. Borrowers pay interest on these.
The margin: the loan rate is higher than the deposit rate, and that difference is the core of the profit.

💵 The Net Interest Margin

Banks turn deposits into loans. When you put money in a savings account, the bank does not leave it in a vault, it lends most of it to other customers. You might earn a modest rate on your deposit, while a borrower pays a higher rate on their mortgage. The bank keeps the gap.

Saver deposits money and earns a lower interest rate

Bank lends that money to a borrower at a higher rate

The difference between the two rates is the net interest margin

Across millions of accounts and loans, this adds up to most of the profit

Why Your Savings Rate Is Usually Lower

This is why an everyday account often pays little or no interest, while a mortgage charges several times more. The bank needs the gap to cover its costs, its risks, and its profit. It also explains why shopping around matters: different banks set different margins, so the saver who compares rates, and the borrower who negotiates, both keep more of the gap for themselves.

Risk Is Part of the Price

Some borrowers do not repay. The bank prices that risk into loan rates, charging more where the risk is higher. That is part of why an unsecured personal loan or a credit card costs far more than a home loan secured against a house.

💰 Fees and the Role of the OCR

Fees and Other Income

Beyond the interest margin, banks earn from a range of fees and services.

Source	Examples
Account and transaction fees	Monthly account fees, overseas transaction fees
Lending fees	Loan establishment fees, credit card annual fees
Penalty fees	Unarranged overdraft and late payment fees
Other services	Insurance, foreign exchange, and merchant services

Many of these fees are avoidable with the right account and good habits, which is why comparing accounts is worthwhile.

How the OCR Feeds In

The Reserve Bank sets the Official Cash Rate, which influences the cost of money across the whole system. When the OCR moves, banks tend to adjust both their lending and deposit rates. The margin can widen or narrow, but the basic model stays the same: lend higher than you borrow, and keep the difference. To go deeper on this, see our guide on how the OCR affects you.

                Why this matters to you: Because savings and loan rates move together and both feed the margin, a rate cut that lowers your mortgage may also lower your savings rate. Understanding the link helps you read rate news as a borrower and a saver at the same time.
            

💡 Using This Knowledge

As a Saver

Since the bank profits from paying you less, it pays to make your savings work harder. Compare savings rates, use higher-interest or bonus saver accounts for money you do not need day to day, and consider a term deposit for money you can lock away. The difference between a no-interest account and a competitive rate is money the bank would otherwise keep.

As a Borrower

Since the bank profits from charging you more, the loan rate is not always fixed in stone. Shopping around, negotiating, and keeping a strong repayment record can all lower the rate you pay. On a mortgage, even a small rate reduction is worth a lot over the life of the loan.

Compare savings rates and use the right account for each job

Avoid unnecessary fees by choosing the right account

Shop around and negotiate on loans, especially the mortgage

Remember the bank profits from the gap, so closing it helps you

A Healthy Perspective

None of this means banks are the enemy. They provide safe storage, payments, and access to credit that the economy relies on. But they are businesses with a clear profit model, and customers who understand that model make sharper choices. Use the Term Deposit Calculator and Mortgage Repayment Calculator to see the numbers for your own situation.

Final word: a bank earns mainly by lending your deposits out for more than it pays you, topped up with fees. Once you see the margin, you can act to keep more of it, by saving smarter and borrowing sharper. This is general information, not personalised financial advice.

🎯 Test Your Knowledge

Quiz on How Banks Make Money (20 Questions)

1. Most of a typical bank profit comes from:

The gap between lending rates and deposit rates

Government grants

Selling shares to customers

Charging to open an account

2. The net interest margin is:

The difference between interest charged and interest paid

A government tax

A type of savings account

The fee to use an ATM

3. When you deposit money in a savings account, the bank:

Lends most of it out to other customers

Leaves it untouched in a vault

Gives it to the government

Spends it on advertising only

4. An everyday account often pays little interest because:

The bank needs the gap to cover costs, risk, and profit

Interest is illegal

The government bans it

Customers ask for zero interest

5. A mortgage usually costs less than a personal loan because:

It is secured against a house, so it is lower risk

Houses are cheap

The government pays it

It is unsecured

6. Banks price risk into loans by:

Charging more where the risk of non-repayment is higher

Charging everyone the same

Ignoring risk

Lowering all rates

7. Besides the interest margin, banks also earn from:

Fees and other services

Only deposits

Only the OCR

Donations

8. Which is an example of a penalty fee?

An unarranged overdraft or late payment fee

Interest you earn

A government rebate

A deposit

9. Many bank fees are:

Avoidable with the right account and good habits

Compulsory on every account

Set by the customer

Refunded automatically

10. The Official Cash Rate is set by:

The Reserve Bank

Each individual bank

The supermarket

Customers voting

11. When the OCR moves, banks tend to:

Adjust both lending and deposit rates

Change only ATM locations

Close accounts

Do nothing

12. A rate cut that lowers your mortgage may also:

Lower your savings rate

Raise your savings rate to record highs

Have no effect on savings

Cancel your loan

13. As a saver, a smart response to the bank model is to:

Compare rates and use higher-interest accounts for spare money

Leave everything in a no-interest account

Never save

Avoid all banks

14. As a borrower, you can reduce what you pay by:

Shopping around, negotiating, and keeping a strong repayment record

Accepting the first rate always

Never repaying

Borrowing more

15. On a mortgage, even a small rate reduction is:

Worth a lot over the life of the loan

Meaningless

Only useful to the bank

Impossible to get

16. A term deposit is useful for:

Money you can lock away for a higher rate

Daily spending money

Money you need tomorrow

Paying for groceries

17. The difference between a no-interest account and a competitive rate is:

Money the bank would otherwise keep

Always tiny

A government fee

Tax you must pay

18. Understanding the bank profit model helps customers:

Make sharper saving and borrowing choices

Avoid banks entirely

Pay more in fees

Ignore rates

19. Banks are best described as:

Businesses with a clear profit model that also provide essential services

Charities

Government departments

The enemy

20. The simplest summary of how a bank earns is:

Lend deposits out for more than it pays you, plus fees

Print its own money

Charge only the government

Earn nothing

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