How to Analyse Bank Stocks

To analyse bank stocks, focus on how a bank makes and protects money: net interest margin and net interest income, return on equity and return on assets, the efficiency ratio, loan quality, and capital strength. A bank is a leveraged lender, so its moat is funding and its biggest risk is bad loans.

Where this fits: banks bend the usual rules, so this guide adapts the Five Criteria framework to financials. Pair it with how to read a balance sheet, because for a bank the balance sheet is the business.

Most investing guides teach you to analyse a company that sells a product, converts sales into profit, and throws off free cash flow. A bank does none of those things in the ordinary way. Its inventory is money, its product is risk, and its balance sheet is not a support act — it is the main performance.

That is why so many investors who are perfectly comfortable with a consumer-goods company freeze up in front of a bank. The good news is that banks reward a systematic approach. Once you know which handful of metrics actually matter, they become more legible, not less.

How a bank actually makes money

A bank earns money in three broad ways, and you should know the mix before anything else.

• Net interest income. The bank borrows cheaply (mostly from depositors) and lends at a higher rate. The gap is its core engine.
• Fee and commission income. Account fees, card interchange, wealth management, advisory, payments. This income does not consume capital the way lending does, so investors often prize it.
• Trading and other income. For investment banks especially, markets activity can be large but is volatile and lower quality.

A retail and commercial bank leans on the first two. An investment bank leans more on the third. The business you are analysing changes completely depending on this mix, so never treat “a bank” as one thing.

Net interest margin: the spread that drives everything

The single most important operating metric for a lending bank is the net interest margin (NIM) — net interest income divided by average interest-earning assets. It tells you how wide a spread the bank earns on the money it puts to work.

A rising NIM usually means the bank can charge more for loans than it pays for deposits. A falling NIM squeezes the engine. NIM moves with interest rates, competition and the bank’s funding mix, so always read it as a trend over several years rather than a single snapshot.

Pair NIM with the cost of funding. A bank that funds itself with sticky, low-cost current-account deposits has a structural advantage over one that relies on expensive wholesale borrowing. That funding advantage is, in effect, a bank’s version of a moat — more on that below.

Profitability: use ROE and ROA, not ROIC

Our framework normally prizes return on invested capital above 15%. For a bank, ROIC is the wrong tool, because a bank’s “invested capital” and its operations are tangled together. Two cleaner measures take its place.

• Return on equity (ROE): net income divided by shareholders’ equity. This is the headline profitability number for banks. A durable 12–15% through a full cycle is strong.
• Return on assets (ROA): net income divided by total assets. Because banks are heavily leveraged, ROA looks small — around 1% is respectable for a traditional bank. ROA strips out the effect of leverage, so it tells you how well the bank earns on its asset base regardless of how much debt it piles on top.

The relationship matters. A bank can lift ROE simply by using more leverage, which flatters the headline while quietly raising risk. If ROE is high but ROA is thin and leverage is rising, you are being paid for risk, not quality.

Metric	What it measures	Rough benchmark
Net interest margin	Spread on earning assets	Stable or rising
Return on equity	Profit on shareholder capital	12–15% through a cycle
Return on assets	Profit regardless of leverage	~1% for a traditional bank
Efficiency ratio	Cost to earn each unit of revenue	40–55% is strong
CET1 ratio	Capital cushion	Comfortably above regulatory minimum

The efficiency ratio: how well-run is it?

The efficiency ratio divides operating costs by revenue. A ratio of 50% means the bank spends 50p to generate every £1 of income. Lower is better, and the best-run banks sit comfortably below 55%.

Efficiency is partly structural — a scale player spreads fixed technology and compliance costs over a larger base — and partly cultural. A management team that lets the cost base drift is telling you something about discipline. Read the efficiency ratio alongside the hierarchy of choices in what great management does with your money.

Loan quality: where banks live or die

Here is the uncomfortable truth about banks: in a good year, almost any bank looks profitable. The difference between a great bank and a dangerous one shows up in a downturn, and it is written in loan quality. Watch four things.

• Non-performing loans (NPLs): loans where borrowers have stopped paying. A rising NPL ratio is an early warning.
• Loan-loss provisions: money the bank sets aside for expected bad loans. Provisions reduce reported profit, so a bank can flatter earnings by under-providing — then pay the price later.
• Net charge-offs: loans actually written off as uncollectable.
• Loan growth versus peers: a bank growing its book far faster than rivals is usually winning that business by accepting weaker borrowers. Fast growth in lending is a yellow flag, not a green one.

The historical pattern is consistent: banks rarely fail because of their mundane years. They fail because they lent aggressively into a boom and the loans turned sour in the bust. Treat conservative underwriting as a feature worth paying for, in the spirit of our guide to red flags in a business.

Capital strength: the balance-sheet test

Our fourth criterion normally checks net debt to EBITDA and interest coverage. Those ratios are meaningless for a bank, because a bank is supposed to be leveraged — that is the model. The equivalent question is whether it holds enough capital to absorb losses.

The key figure is the CET1 (Common Equity Tier 1) ratio — the bank’s highest-quality capital as a percentage of its risk-weighted assets. Regulators set minimums; a prudent bank runs comfortably above them, giving itself room to keep lending through a recession rather than being forced to raise capital at the worst moment.

A well-capitalised bank is boring in a crisis, and boring is exactly what you want. A thinly capitalised bank with an aggressive loan book is where permanent losses are made.

Does a bank have a moat?

Banking looks like a commodity — money is money — yet some banks earn durable returns for decades. The durable advantages tend to be:

• A low-cost deposit base. Millions of households keeping current accounts with the same bank out of inertia is a cheap, sticky funding source rivals cannot easily copy.
• Scale. Fixed costs in technology, branches, compliance and brand spread over a huge balance sheet.
• Switching costs. Mortgages, direct debits and payroll are a hassle to move, so customers stay.

These are real but modest moats. Apply the same test you would in how to spot a competitive advantage: can the bank keep earning above its cost of capital even when rivals try to take its customers? If the only edge is being willing to lend more cheaply, that is not a moat — it is a risk.

Valuing a bank

Because free cash flow is awkward for banks, valuation leans on two anchors.

• Price to tangible book value (P/TBV). Tangible book value is equity minus goodwill and intangibles — roughly what shareholders would be left with if the bank were wound down. A high-ROE bank deserves to trade above tangible book; a low-ROE or troubled bank often trades below it. Build on the logic in our guide to price to book value.
• Normalised earnings and dividends. Because provisions swing earnings around, estimate a mid-cycle, normalised profit rather than extrapolating a boom year. A sustainable dividend, well covered by earnings and capital, is a useful reality check.

A hypothetical sense-check

Imagine a bank, Bank A. It earns a steady 13% ROE, keeps its efficiency ratio near 50%, holds capital well above the regulatory minimum, and grows its loan book roughly in line with the economy. It trades at 1.1x tangible book. That profile — strong, disciplined, conservatively capitalised, reasonably priced — is the kind that rewards patience.

Now imagine Bank B. Its ROE is a flashy 20%, but ROA is thin, leverage is climbing, the loan book is growing twice as fast as peers, and it trades at 2x tangible book. Bank B looks better on the headline and is far more dangerous. (Both are illustrations, not real companies.) The discipline of demanding a margin of safety matters more, not less, when leverage magnifies every mistake.

Frequently Asked Questions

Why can’t I value a bank on free cash flow like other companies? A bank’s cash flows are hard to separate from its financing, because lending and deposit-taking are its operations rather than a way to fund them. Analysts therefore value banks on tangible book value, return on equity and dividends rather than free cash flow.

What is a good return on equity for a bank? A sustainable ROE of 12–15% across a full economic cycle is generally considered strong. Figures far above that often reflect excess leverage or an unusually benign credit environment rather than durable quality, so always check ROA and capital alongside it.

What is the efficiency ratio and why does it matter? It is operating costs divided by revenue — how much a bank spends to earn each unit of income. Lower is better; the strongest banks sit in the 40–55% range, and a persistently high ratio points to a bloated cost base or weak pricing power.

How do I know if a bank is taking too much risk? Look at the CET1 capital ratio, the trend in non-performing loans, how fast the loan book is growing relative to peers, and the size of loan-loss provisions. Rapid loan growth combined with thin capital is a classic recipe for trouble.

Are investment banks analysed the same way as retail banks? No. Investment banks rely more on trading and advisory income, which is volatile and capital-intensive, so their earnings are lower quality and harder to predict. The core tools — capital strength, ROE, book value — still apply, but you should demand a wider margin of safety.

Your Next Step

Banks reward investors who respect the balance sheet and resist the temptation of a flattering headline ROE. Before you buy one, work through these:

• How to read a balance sheet — essential, because for a bank the balance sheet is the business.
• Return on invested capital — to understand the quality standard you are adapting for financials.
• The Five Criteria scorecard calculator — to score a bank consistently against your framework.

For deeper sector playbooks and ready-made analysis templates, see our premium resources.

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About the author: Cameron Hayes is a senior investor relations and finance professional who has worked in IR at Nasdaq Copenhagen-listed companies including Nilfisk and Maersk Drilling. He holds an MSc from Copenhagen Business School and a BCom from the University of Ottawa, and founded Gingernomics to teach individual investors the Five Criteria framework. More about Gingernomics.

The content on Gingernomics is for educational and informational purposes only and does not constitute financial advice. Always do your own research and consult a licensed financial advisor before making any investment decisions. Past performance is not indicative of future results.