Author: Taylor Warfield, Former Bain Manager and interviewer

Last Updated: May 16, 2026

 

A banking case interview is a 30 to 45 minute exercise where you solve a business problem for a bank. You analyze data, build a framework, and deliver a recommendation, just like a real consulting engagement.

 

Banking cases show up at almost every firm with a financial services practice. According to McKinsey's Global Banking Annual Review, banks generate roughly $7 trillion in annual revenue worldwide, which is why top consulting firms staff large banking teams.

 

This guide walks you through the four types of banking cases, the financial metrics you must know, and a full worked example. I draw on my experience as a former Bain Manager and interviewer who has helped over 3,000 candidates land consulting offers.

 

But first, a quick heads up:

 

McKinsey, BCG, Bain, and other top firms accept less than 1% of applicants every year. If you want to triple your chances of landing interviews and 8x your chances of passing them, watch my free 40-minute training.

 

What Is a Banking Case Interview?

 

A banking case interview tests whether you can solve a real business problem for a commercial, retail, investment, or digital bank. You will get a prompt such as "should a regional bank expand into wealth management" or "why has our retail bank's profit dropped 20%," and you need to structure your thinking, work through the math, and deliver a recommendation in 30 to 45 minutes.

 

These cases differ from regular cases because banks have unusual financial structures. Loans are assets, deposits are liabilities, and profitability depends heavily on credit risk, capital requirements, and interest rate spreads. Treating a bank case like a retail profitability case will get you rejected.

 

In my experience interviewing candidates at Bain, the difference between a good answer and a great one came down to whether the candidate could layer banking knowledge on top of standard problem-solving. Candidates who knew net interest margin, return on equity, and the cost-to-income ratio cold consistently outperformed those who did not.

 

Which Firms Use Banking Case Interviews?

 

Banking cases appear at two groups of employers. Consulting firms with banking practices use them to screen for financial services roles. Banks themselves use case-style interviews for in-house strategy hires and certain analyst positions.

 

On the consulting side, all of MBB plus Oliver Wyman, Deloitte, PwC (Strategy&), Accenture, and Kearney use banking cases for their financial services practices. Oliver Wyman is the most banking-heavy firm, with roughly 60% of their work in financial services.

 

On the corporate side, Capital One is famous for case-based interviews with a heavy banking lens. American Express, JPMorgan Chase, and Goldman Sachs also use case-style questions for certain strategy and operations roles. If you are interviewing at any of these firms, expect at least one banking case.

 

What Are the Four Main Types of Banking Cases?

 

Banking cases break down into four categories based on the type of bank involved. The questions, frameworks, and metrics change depending on which type you get, so prepare for all four.

 

The four banking case types are:

 

• Retail banking

 

• Commercial banking

 

• Investment banking

 

• Digital banking and fintech

 

What Is a Retail Banking Case?

 

A retail banking case focuses on banks that serve individual consumers. Products include checking accounts, savings accounts, mortgages, auto loans, credit cards, and wealth management. Typical prompts ask whether a retail bank should add new branches, launch a new product, acquire a smaller competitor, or improve customer retention.

 

Retail banking is the most common type of banking case because retail banks are large, well-known, and easy for interviewers to build cases around. Roughly half of all banking cases at MBB firms are retail banking cases, based on candidate reports.

 

The key drivers are customer acquisition cost, customer lifetime value, cross-sell rates, and net interest margin. You should also think about the cost-to-serve gap between branches and digital channels. According to McKinsey research, the cost to acquire a customer through a branch can be 5x to 10x higher than acquiring through digital channels.

 

What Is a Commercial Banking Case?

 

A commercial banking case focuses on banks that serve businesses, from small companies to large corporations. Products include business loans, commercial real estate financing, treasury management, trade finance, and equipment leasing. Common prompts include whether a commercial bank should expand into a new industry vertical or how to grow share of wallet with existing clients.

 

Commercial banking has higher revenue per client than retail banking but also higher credit risk. The average commercial loan size is much larger, so a single default can wipe out the profit from many performing loans.

 

You should know about loan-to-deposit ratios, commercial lending spreads, and concentration risk. Top commercial banks aim for a loan-to-deposit ratio between 70% and 85%, which balances earning potential with liquidity.

 

What Is an Investment Banking Case?

 

An investment banking case focuses on banks that help companies raise capital or execute mergers and acquisitions. Revenue comes from advisory fees, underwriting fees, trading profits, and prime brokerage. Common prompts include whether an investment bank should expand into a new market, build out a specific industry coverage group, or invest in new trading technology.

 

These cases are less common in consulting interviews because consulting firms work with corporates rather than running trading desks. But Oliver Wyman, BCG, and McKinsey all serve investment banks, so the cases do appear.

 

Investment banking economics depend on deal flow, league table rankings, and headcount efficiency. Top firms target revenue per banker of $1.5 million to $2 million annually. Trading desks operate under Value at Risk (VaR) limits, regulatory capital constraints, and bid-ask spreads.

 

What Is a Digital Banking or Fintech Case?

 

A digital banking case focuses on neobanks, online-only banks, or fintech challengers like Chime, Revolut, or SoFi. Common prompts include how a neobank should achieve profitability, whether a digital bank should add new products, or how a traditional bank should compete against digital challengers.

 

These cases have grown rapidly because fintech is one of the hottest areas in consulting. According to PwC's 2025 fintech report, global fintech revenue is projected to exceed $400 billion by 2028, growing roughly 3x faster than traditional banking.

 

Key concepts include unit economics on digital customer acquisition, embedded finance, interchange revenue, and the path to profitability for neobanks. Most neobanks lose money for the first 5 to 7 years before reaching scale.

 

How Do the Four Types Compare?

 

The table below maps each banking case type to its main revenue drivers, key metrics, and most likely case prompts.

 

Case Type	Main Revenue	Key Metrics	Common Prompts
Retail Banking	Net interest income, deposit fees	NIM, customer acquisition cost, cross-sell ratio	New product launch, branch strategy, retention
Commercial Banking	Loan spreads, treasury fees	Loan-to-deposit ratio, credit loss rate	Vertical expansion, share of wallet, credit policy
Investment Banking	Advisory and underwriting fees, trading	Revenue per banker, league table rank, VaR	Industry coverage build-out, trading technology, market entry
Digital Banking & Fintech	Interchange, subscription, interest	Customer acquisition cost, contribution margin, take rate	Path to profitability, product expansion, fintech competition

 

How Do Banks Make Money?

 

Banks have three main revenue sources: net interest income, fee income, and trading income. Most retail and commercial banks earn 60% to 70% of revenue from net interest income.

 

Net interest income is the spread between what banks pay depositors and what they charge borrowers. If a bank pays 2% on deposits and charges 6% on loans, it earns a 4% net interest margin. Multiplied across billions in earning assets, this becomes the largest revenue line for most banks.

 

Fee income includes account fees, transaction fees, advisory fees, mortgage origination fees, and credit card interchange. Fees are attractive because they do not depend on interest rate movements. Trading and investment income is concentrated at investment banks but also appears at large universal banks.

 

On the cost side, banks face four main expense categories. These are interest expense, credit losses, operating costs, and regulatory costs. The cost-to-income ratio tracks how efficiently the bank converts revenue into profit.

 

According to McKinsey's Global Banking Annual Review, top-performing banks achieve a cost-to-income ratio below 55%, while struggling banks operate above 70%.

 

What Banking Metrics Should You Know?

 

You should memorize six core banking metrics before any banking case interview. These metrics let you sense-check your math and ask sharper questions during the case.

 

Metric	What It Measures	Healthy Range
Return on Equity (ROE)	Profit per dollar of shareholder capital	10% to 15%
Net Interest Margin (NIM)	Interest spread as % of earning assets	2.5% to 3.5% for U.S. banks
Cost-to-Income Ratio	Operating expenses / total revenue	50% to 65% (lower is better)
Loan-to-Deposit Ratio	Loans / deposits	70% to 85%
Tier 1 Capital Ratio	Core capital / risk-weighted assets	Minimum 6%, most target 10%+
Net Charge-Off Rate	Loan losses / total loans	0.3% to 1.0% in normal times

 

If your math gives you an ROE above 25% or a cost-to-income ratio under 30%, something is wrong. Use these ranges to catch math errors in real time during the case.

 

What Framework Should You Use for a Banking Case?

 

There is no single framework that fits every banking case. The best approach is to tailor your structure to the specific prompt, drawing on your knowledge of how banks operate.

 

For a bank profitability case, structure around four buckets: revenue drivers, cost drivers, capital and regulation, and competitive dynamics. Revenue splits into net interest income, fees, and trading. Costs split into interest expense, credit losses, operating costs, and regulatory expenses.

 

For a bank growth or market entry case, use five buckets: market attractiveness, competition, bank capabilities and synergies, financial returns and capital requirements, and regulatory approval. Regulation should always appear somewhere in your structure.

 

For a bank cost reduction case, structure around branch network, headcount and operating model, technology and automation, vendor and procurement, and regulatory compliance overhead. Banks have unusually high fixed costs from branches and compliance staff, which makes these levers different from other industries.

 

The deeper principle is that you should build case interview frameworks by starting from the specific prompt and working backwards to the buckets you need. Generic templates fail in banking because they ignore credit risk and capital.

 

How Do You Solve a Banking Case in 4 Steps?

 

Banking cases follow the same four-step structure as any case interview. The difference is that you must layer banking-specific knowledge into each step.

 

Step 1: Understand the Bank's Business Model

 

Start by confirming what kind of bank the client is. Ask about the bank's product mix, customer segments, geographic footprint, and current performance. The case for a regional commercial bank looks very different from the case for a global investment bank.

 

A strong opening might sound like this: "To make sure I understand, our client is a U.S. retail bank with 500 branches operating in five states. They primarily serve mass-market and mass-affluent customers with checking, savings, and mortgage products. Is that correct?"

 

If the interviewer mentions a term you do not know, ask. Saying "could you tell me what Tier 1 capital means in this context" is far better than guessing wrong.

 

Step 2: Build a Banking-Specific Framework

 

Take 2 to 3 minutes to lay out your framework. Make it specific to banking, not generic.

 

For a profitability case, walk the interviewer through revenue, costs, capital, and competition. For a market entry case, walk through market, competition, capabilities, financials, and regulation. State the framework before you start any analysis. The MECE framework principle still applies, so your buckets should not overlap and should cover the full problem.

 

Step 3: Run the Numbers

 

Banking cases tend to be more quantitative than average cases. You should be ready to calculate net interest margin, return on equity, return on assets, fee revenue, credit loss rates, and break-even on new initiatives.

 

Sense-check your math against industry benchmarks. A healthy U.S. bank earns an ROE of 10% to 15%. A net interest margin of 2.5% to 3.5% is typical. If your number is way off, double-check your assumptions before moving on.

 

Practicing case interview math is the single best way to feel confident with banking calculations. The math is rarely complicated. Speed and accuracy under pressure are what matter.

 

Step 4: Deliver a Sharp Recommendation

 

Lead with a clear answer. Say "I recommend the bank expand into wealth management" or "I recommend against the acquisition." Do not hedge with "it depends."

 

Follow with two to three supporting reasons backed by the analysis you completed. End with risks and next steps. If the interviewer pushes back, do not immediately reverse your position. Acknowledge the concern, explain your reasoning, and discuss mitigations.

 

Banking Case Interview Example: A Worked Walkthrough

 

Let me walk through a complete banking case end to end. This is the kind of case I gave to candidates as a Bain interviewer, similar to what you would see in an MBB first round.

 

What Is the Case Prompt?

 

Your client is Heartland Bank, a regional U.S. retail bank with $30 billion in assets and 300 branches across four states in the Midwest. Heartland's profit has dropped 25% over the past two years, from $400 million to $300 million. The CEO wants to know what is driving the decline and how to fix it.

 

How Do You Structure the Case?

 

Confirm the case prompt first: "Our client is Heartland Bank, a regional retail bank with $30 billion in assets and 300 branches. Profit has fallen 25% from $400 million to $300 million over two years. We want to identify what is driving the decline and recommend fixes. Is that right?"

 

Then ask clarifying questions. Has the bank acquired or divested anything recently? Has the customer base changed? Are competitors experiencing the same trend?

 

Structure your profitability case interview framework around four buckets:

 

• Revenue: net interest income and fee income

 

• Costs: operating costs, credit losses, and interest expense

 

• Capital and balance sheet: loans, deposits, and capital ratios

 

• External factors: interest rates, competition, and regulation

 

What Does the Math Look Like?

 

Suppose the interviewer tells you that Heartland's revenue stayed flat at $1.5 billion, operating costs rose from $900 million to $1 billion, and credit losses jumped from $200 million to $300 million.

 

Revenue is flat at $1.5 billion, so there is no top-line issue. Operating costs are up $100 million, an 11% increase. Credit losses are up $100 million, a 50% increase, which is the bigger problem.

 

The credit loss increase explains $100 million of the profit drop, and the cost increase explains another $100 million. That is $200 million in total pressure, but profit only fell by $100 million. So something else helped.

 

The interviewer might then reveal that interest expense fell by $100 million because the bank let go of expensive brokered deposits. That partially offset the credit loss spike.

 

Now you know the real story. The bank is being hit by a credit loss problem, masked partially by lower funding costs. The next questions to ask are: which loan categories are deteriorating, and is the credit problem cyclical or structural?

 

What Is the Recommendation?

 

"Heartland's profit decline is being driven primarily by a 50% increase in credit losses, partially offset by lower funding costs. The next two years should focus on three priorities."

 

First, tighten underwriting on the loan categories driving losses. If commercial real estate is the problem area, reduce concentration and apply tougher lending standards.

 

Second, reduce operating costs by 5% over 18 months through branch consolidation in underperforming markets and back-office automation. This should free up roughly $50 million annually.

 

Third, grow fee income by 10% by pushing wealth management cross-sell to existing customers. This is a fast way to add high-margin revenue without taking on additional credit risk.

 

Key risks include continued credit cycle deterioration, which would require more aggressive provisioning. I would recommend stress-testing the loan book before committing to the cost-reduction plan.

 

What Are the Most Common Mistakes in Banking Cases?

 

Having interviewed hundreds of candidates, I see the same mistakes again and again in banking cases. Avoiding them will immediately set you apart.

 

• Using a generic profitability framework. Candidates who walk in with a memorized 3-bucket profitability template get tripped up the moment regulation or capital enters the case. Banking is unique and your framework has to reflect that.

 

• Ignoring regulation entirely. Every banking case has a regulatory dimension. You do not need to be an expert, but acknowledging that regulation constrains the client's options shows business maturity.

 

• Confusing retail, commercial, and investment banking economics. Retail banks earn on deposits and consumer loans. Commercial banks earn on business loans. Investment banks earn on fees and trading. Mixing these up signals weak preparation.

 

• Forgetting the bank balance sheet structure. Loans are assets and deposits are liabilities, which is the opposite of how most people think about money. Get this wrong and the entire case unravels.

 

• Skipping the sense-check. Banking math can get complex. If your calculated ROE is 50% or your charge-off rate is 10%, you have made an error. Always benchmark against typical industry ranges.

 

• Panicking on unfamiliar terms. You will not know every banking term. The correct response is to ask the interviewer to explain it. First-principles thinking beats memorized jargon every time.

 

How Should You Prepare for Banking Case Interviews?

 

A practical preparation plan has three parts: build banking knowledge, practice cases, and master banking math. Most candidates need 4 to 8 weeks of total case prep, with the final 1 to 2 weeks focused on banking specifics.

 

How Do You Build Banking Knowledge?

 

Start by reading the annual reports of one large U.S. bank such as JPMorgan Chase and one regional bank such as PNC or US Bancorp. Annual reports explain the business model in plain English and show you how real banks talk about their strategy.

 

Skim McKinsey's Global Banking Annual Review for current industry themes like digital transformation, interest rate normalization, and fintech competition. These topics appear in cases because interviewers draw from real industry challenges.

 

Memorize the six core banking metrics from the table earlier in this guide. Knowing typical ranges (ROE 10% to 15%, NIM 2.5% to 3.5%, cost-to-income 50% to 65%) gives you instant sense-checking ability during the case.

 

How Should You Practice Banking Cases?

 

Do at least 15 practice cases total, with 5 to 8 banking-specific cases. Free banking cases are available on the careers pages of MBB, Oliver Wyman, and Capital One. Practice with a partner who has at least some financial services knowledge if possible.

 

If you are targeting Capital One specifically, their case interviews are heavier on math and lighter on framework than MBB. Their published practice case is essential preparation. Plan to do at least 3 timed practice runs of that case before your interview.

 

My case interview course includes a dedicated module on banking and financial services cases with drills and worked examples. It is the fastest way to move from average to top 10% on these cases.

 

How Do You Master Banking Math?

 

Drill on net interest margin, ROE, ROA, and break-even calculations. You should be able to calculate that a bank with $50 billion in assets and a 3% NIM earns roughly $1.5 billion in net interest income without hesitation.

 

Practice mental math with banking-style numbers. Multiplying $30 billion times 0.5% (a typical credit loss rate) to get $150 million should feel automatic. Slow math during a banking case is the fastest way to lose the interviewer's confidence.

 

Frequently Asked Questions

 

Do You Need a Finance Degree to Pass Banking Cases?

 

No. Most successful candidates do not have a finance background. You need to learn the core banking metrics and business model, which takes 3 to 5 hours of focused study. Interviewers care about your problem-solving approach, not your finance credentials.

 

How Is a Banking Case Different from a Regular Profitability Case?

 

A regular profitability case looks at revenue minus cost. A banking profitability case adds two more layers: credit losses, which can swing wildly year to year, and capital requirements, which constrain how aggressively a bank can grow. Both need to be in your framework for banking cases.

 

What Banking Metrics Are Most Likely to Come Up?

 

The metrics that come up most often are net interest margin, return on equity, cost-to-income ratio, and loan-to-deposit ratio. You should know typical ranges for each. Healthy banks earn ROE of 10% to 15%, NIM of 2.5% to 3.5%, and run cost-to-income at 50% to 65%.

 

Are Banking Cases Harder Than Other Case Types?

 

Banking cases feel harder because they require industry knowledge most candidates lack. But once you have spent 3 to 5 hours learning the basics, banking cases are no harder than any other industry case. The frameworks and problem-solving approach are identical.

 

How Long Should You Prepare for Banking Case Interviews?

 

Most candidates need 4 to 8 weeks of total case prep, with the final 1 to 2 weeks focused specifically on banking. If you are interviewing for a banking-focused firm like Oliver Wyman or Capital One, spend at least 3 weeks on banking content. For a generalist firm where banking is one of many industries, 1 to 2 weeks of focused banking prep is enough.

 

Where Can You Find Free Banking Practice Cases?

 

The best free banking cases come straight from the consulting firms. McKinsey publishes the Diconsa case on rural financial services. Oliver Wyman publishes the Wumbleworld case with banking-style economics. Capital One publishes a full practice case on their careers page that is heavy on banking math.

 

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