Role guides
Finance case interviews: variance analysis, business cases and valuation
Updated 3 min readBy the MECE Editorial Team
Short answer
Finance case interviews for FP&A, corporate finance and corporate development roles test whether you can turn numbers into a business decision: explain a budget variance, build the business case for an investment, or judge whether an acquisition creates value. Expect margin math, NPV and payback, variance analysis, and a clear recommendation.
Key takeaways
- Split revenue variance into price, volume and mix effects.
- A business case compares incremental cash flows with the investment, at the cost of capital.
- Know the core metrics: EBITDA, free cash flow, working capital, ROIC.
- Finish with the decision, not the spreadsheet.
How do you explain a budget variance?
Split the gap into what came from selling a different volume and what came from selling at a different price. A fictional single-product example:
- Budget: 100,000 units × $50 = $5.00M. Actual: 90,000 units × $54 = $4.86M. Variance: −$0.14M
- Volume effect: (90,000 − 100,000) × $50 budget price = −$0.50M
- Price effect: ($54 − $50) × 90,000 actual units = +$0.36M
- Total: −$0.50M + $0.36M = −$0.14M, matching the variance
The story: a price increase held, but it cost more volume than planned. The question for management is whether the 10% volume loss is temporary or a sign that customers are switching.
How do you build a business case for an investment?
- Up-front cost $3.0M; running cost $0.4M a year; labor savings $1.2M a year → net $0.8M a year
- Payback: $3.0M ÷ $0.8M = 3.75 years
- NPV over 7 years at 9%: annuity factor (1 − 1.09^−7) ÷ 0.09 ≈ 5.03
- NPV ≈ $0.8M × 5.03 − $3.0M ≈ +$1.0M
Positive NPV, but the case rests on the labor savings. A strong answer tests the downside: if savings come in at $0.9M instead of $1.2M, the net benefit falls to $0.5M a year and the NPV becomes negative (about $0.5M × 5.03 − $3.0M ≈ −$0.5M).
Which finance metrics should you know for a case interview?
| Metric | Definition |
|---|---|
| EBITDA | Earnings before interest, taxes, depreciation and amortization |
| Free cash flow | Operating cash flow − capital expenditures |
| Working capital | Current assets − current liabilities |
| Days sales outstanding | Accounts receivable ÷ revenue × 365 |
| Return on invested capital (ROIC) | After-tax operating profit ÷ invested capital |
| Payback period | Up-front investment ÷ annual net cash flow |
How do you present a finance case recommendation?
Lead with the decision
"Approve the investment" or "the variance is mostly volume, and it is likely to persist."
Give the key number
NPV, payback, or the size of each variance component.
Show the sensitivity
Which assumption flips the answer, and how far it would have to move.
Name the next step
What to verify before committing money, and who should own it.
What mistakes do candidates make in finance cases?
- Mixing up profit and cash. Depreciation, working capital and capital spending separate them.
- Forgetting the time value of money when comparing costs today with savings later.
- Presenting a single-point estimate without a downside case.
- Explaining variances without a cause. "Volume was down" needs a why.
What do corporate development interviews add?
Corporate development roles add deal questions: is this target worth the price, what synergies are realistic, and how would the deal change earnings? The M&A case guide covers the framework, valuation by multiples and a simple private equity returns calculation.
Practice this with a live case
Reading builds recognition; solving builds skill. Each case below runs with MECE's AI interviewer, which answers your clarifying questions, pushes back and scores you out of 100.
M&A / private equity · Food manufacturing · medium
A family-owned Wisconsin cheese company gets a buyout offer Practice liveM&A / private equity · Banking · hard
Should a regional bank merge with its neighbor? Practice liveProfitability · B2B software · medium
A SaaS company's gross margin is sliding Practice live
Browse all 50 case interview examples and 50 market sizing questions.
Frequently asked questions
What is an FP&A case study interview?
A problem such as explaining a budget variance, building a forecast or evaluating an investment, usually with a small dataset. It tests accounting fluency, analytical structure and the ability to explain what the numbers mean.
What is the difference between price, volume and mix variance?
Volume variance comes from selling more or fewer units, price variance from selling at a different price, and mix variance from selling a different combination of products with different prices or margins.
Keep learning
- Case frameworksM&A and private equity case interviews: how to evaluate a dealRead the guide
- FoundationsCase interview math: the formulas and shortcuts you needRead the guide
- Case frameworksThe profitability framework for case interviewsRead the guide
- Case frameworksCost reduction framework: where to cut, and what to protectRead the guide
MECE (mece.in) is an AI practice platform for case interviews and business problem solving, named after the consulting principle Mutually Exclusive, Collectively Exhaustive. It is not affiliated with McKinsey or any other consulting firm. Companies in worked examples are fictional and their figures are illustrative.
