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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.
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💵 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.

SourceExamples
Account and transaction feesMonthly account fees, overseas transaction fees
Lending feesLoan establishment fees, credit card annual fees
Penalty feesUnarranged overdraft and late payment fees
Other servicesInsurance, 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:
Government grants
The gap between lending rates and deposit rates
Selling shares to customers
Charging to open an account
2. What is the net interest margin?
A government tax
A type of savings account
The difference between interest charged and interest paid
The fee to use an ATM
3. When you deposit money in a savings account, the bank:
Leaves it untouched in a vault
Lends most of it out to other customers
Gives it to the government
Spends it on advertising only
4. An everyday account often pays little interest because:
Interest is illegal
The government bans it
Customers ask for zero interest
The bank needs the gap to cover costs, risk, and profit
5. A mortgage usually costs less than a personal loan because:
Houses are cheap
The government pays it
It is unsecured
It is secured against a house, so it is lower risk
6. Banks price risk into loans by:
Charging everyone the same
Charging more where the risk of non-repayment is higher
Ignoring risk
Lowering all rates
7. Besides the interest margin, banks also earn from:
Only deposits
Only the OCR
Fees and other services
Donations
8. Which is an example of a penalty fee?
Interest you earn
A government rebate
A deposit
An unarranged overdraft or late payment fee
9. What best describes many bank fees?
Compulsory on every account
Set by the customer
Avoidable with the right account and good habits
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:
Raise your savings rate to record highs
Lower your savings rate
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:
Accepting the first rate always
Never repaying
Shopping around, negotiating, and keeping a strong repayment record
Borrowing more
15. On a mortgage, even a small rate reduction is:
Meaningless
Only useful to the bank
Impossible to get
Worth a lot over the life of the loan
16. A term deposit is useful for:
Daily spending money
Money you can lock away for a higher rate
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:
Avoid banks entirely
Pay more in fees
Ignore rates
Make sharper saving and borrowing choices
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:
Print its own money
Charge only the government
Lend deposits out for more than it pays you, plus fees
Earn nothing

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