Most candidates stockpile case interview examples the way undergrads stockpile flashcards. They memorize a foundry, a coffee chain, a pharma launch, and then freeze when the interviewer opens with a marina or a cold-storage operator they have never seen. The sheet does not reward industry trivia. It rewards a short sequence of moves under pressure: clarify the decision, build a structure that fits this prompt, read one exhibit correctly, run math that can flip the answer, and close with a number plus a risk.
That is the thesis of this page. Below you get two fully worked original mini-cases — invented companies, internally consistent numbers — so you can watch the sequence in real time. After that, I point you to the firms' own published practice cases. Those are the primary sources for format. These mini-cases are for the scoring moves.
When you finish, you should be able to open any blank prompt, run the same five moves, and know whether your practice reps are teaching you casing or just teaching you stories.
What an example is for (and what it is not)
A good case interview example is a transparent walkthrough of how an answer gets built. A bad one is an answer key you try to replay. Firms publish sample cases so candidates see the shape of the conversation: McKinsey's interviewing page lists interviewer-led practice cases with logic and suggested answers; Bain's case interview preparation page links written cases such as Coffee Shop Co. and FashionCo.; Deloitte's case and scenario tips page links to its interactive practice tools; BCG's case interview preparation hub explains how it frames problem-solving interviews.
None of those pages is a secret vault of "real" live cases. They are teaching tools. Treat them that way. Steal the move from every example you study: Which clarification changed the tree? Which cell in the table flipped the math? Where did the recommendation get a number?
Ned's rule. If you cannot point to the one number that would reverse your recommendation, you do not yet have a case answer. You have a story with a confident tone.
Mini-case 1 — Profitability: HarborPeak Marinas
Prompt. HarborPeak runs 12 coastal marinas on the US East Coast. Last year EBIT was $18.4m. This year it is $12.1m. Slip occupancy is up slightly. The CEO wants to know why profit fell and what to do in the next 90 days.
Clarify (30 seconds). Compare this fiscal year to last. Success metric is EBIT, not occupancy. No marina sales or dry-stack conversions in scope. Fuel and restaurant are in the P&L; boat brokerage is not.
Structure. Revenue (slip rate × occupied slips, fuel gallons × margin, F&B tickets) and cost (dock labor, utilities, maintenance, insurance, marina overhead). Hypotheses up front: either mix shifted toward lower-margin fuel, or cost per occupied slip jumped — occupancy alone will not explain a $6.3m EBIT hit if volume is flat-to-up.
Exhibit. The interviewer hands you this bridge for the 12-marina portfolio (figures in $m):
| Line item | Prior year | This year | Delta |
|---|---|---|---|
| Slip revenue | 42.0 | 43.1 | +1.1 |
| Fuel contribution | 9.6 | 6.8 | −2.8 |
| F&B contribution | 4.2 | 4.0 | −0.2 |
| Dock labor | 14.0 | 16.7 | −2.7 |
| Utilities + maintenance | 11.0 | 12.4 | −1.4 |
| Overhead / insurance | 12.4 | 12.7 | −0.3 |
| EBIT | 18.4 | 12.1 | −6.3 |
Math you say out loud. Slip revenue up $1.1m on higher occupancy — demand is not the problem. Fuel contribution down $2.8m is the largest single leak; dock labor up $2.7m is the second. Together they explain $5.5m of the $6.3m hit. Utilities and maintenance add another $1.4m. Rough check: if occupied slips rose ~3% and dock labor rose ~19% ($16.7 / $14.0 − 1), labor per slip is the overtime / contractor story, not a volume story.
Ask for one more fact. Interviewer: fuel gallons sold were flat; wholesale diesel rose and HarborPeak held pump prices for members. Labor overtime hours rose 28% after two marinas cut scheduled staff and covered peaks with contractors.
So-what. This is a margin and staffing problem dressed up as "profitability." A volume promo on slips would make the labor problem worse.
Recommendation. Do not cut slip rates. In 90 days: (1) raise member pump prices to restore ~$0.18/gallon contribution on the ~15.5m gallons implied by the old $9.6m contribution at ~$0.62/gallon — or renegotiate the wholesale contract — targeting ~$2m of the fuel leak; (2) restore scheduled dock coverage at the two overtime marinas and cap contractor hours, aiming to claw back ~$1.5m of the labor delta before peak season; (3) defer non-critical maintenance that is not safety-related. Risk: member backlash on fuel prices. Next exhibit you want: member churn after a $0.10 pump test at two sites.
Mini-case 2 — Entry: FrostLine Cold Storage automation
Prompt. FrostLine operates five refrigerated warehouses in the Midwest. Capex proposal: install automated storage and retrieval (AS/RS) at the three largest sites. Board wants a go / no-go for a three-year payback screen. Organic build only; no JV.
Clarify. Decision is three-site AS/RS vs status quo. Metric: simple payback under three years on incremental EBITDA, not strategic optionality. Labor union contracts allow headcount reduction with 12 months' notice. Throughput demand is stable.
Structure. Capex outlay, labor savings, energy / maintenance delta, utilization risk if volume falls, implementation downtime. Hypotheses: automation only clears a three-year hurdle if labor savings are large and the sites run near capacity; a two-site pilot may beat a three-site bet if the third site is half-idle.
Exhibit. Site economics the interviewer provides:
| Site | Annual pallets | Current dock+pick FTEs | Fully loaded cost / FTE ($000) | AS/RS capex ($m) | FTEs after AS/RS |
|---|---|---|---|---|---|
| Aurora | 1.20m | 74 | 78 | 9.5 | 28 |
| Joliet | 0.95m | 61 | 76 | 8.2 | 24 |
| Des Moines | 0.55m | 38 | 72 | 7.1 | 18 |
| Total (3) | 2.70m | 173 | — | 24.8 | 70 |
Math. Labor savings: Aurora (74 − 28) × $78k = $3.59m; Joliet (61 − 24) × $76k = $2.81m; Des Moines (38 − 18) × $72k = $1.44m. Total ~$7.84m / year before energy. Interviewer adds: net energy and maintenance rise $0.6m / year; one-time ramp downtime costs $1.2m in year 1 only. Steady-state incremental EBITDA ≈ $7.84m − $0.6m = $7.24m. Simple payback on $24.8m ≈ 24.8 / 7.24 ≈ 3.4 years — fails the three-year screen. Aurora alone: $9.5m / ($3.59m − share of energy). Allocate energy by pallet share (~44%): $9.5 / (3.59 − 0.26) ≈ 2.9 years. Joliet ≈ 8.2 / (2.81 − 0.21) ≈ 3.2 years. Des Moines ≈ 7.1 / (1.44 − 0.13) ≈ 5.4 years.
So-what. The three-site package fails the board's hurdle because Des Moines dilutes the return. Aurora clears; Joliet is borderline; Des Moines does not.
Recommendation. No on the three-site package. Yes on Aurora now; run Joliet as a year-2 decision after Aurora's utilization and downtime are proven; keep Des Moines manual. Risk: union notice period slips Aurora's year-1 savings. Next: a 13-week Aurora implementation plan with a labor-savings tracking dashboard the board can audit monthly.
How to steal the moves without memorizing industries
Across both cases the industry was noise. The scoring sequence was identical:
| Move | What the interviewer listens for | Failure mode |
|---|---|---|
| Clarify | Decision, metric, constraints in under a minute | Diving into a MECE tree before you know the question |
| Structure | Hypotheses tied to this prompt | Reciting a generic profitability framework |
| Exhibit | One insight from the table, said in a sentence | Reading every cell aloud |
| Math | A calculation that can flip the rec | Beautiful arithmetic with no so-what |
| Close | Numbered action, risk, next fact | A vague "I'd look into costs" |
Practice until you can narrate that table from memory. Then open a firm-published case and force yourself to write the five moves on a blank page before you peek at the suggested answer.
For type definitions (profitability vs entry vs ops vs M&A), use the case interview types guide. For a longer map of free official materials, see free case interview prep resources.
Where the firms publish their own examples
Use the primary sources. URLs move; start from the careers hubs and follow the live links.
| Firm | What they publish (as of 2026-09) | Start here |
|---|---|---|
| McKinsey | Interviewer-led practice cases (e.g. Beautify, Diconsa, Electro-Light, Talbot Trucks, national education) with logic and suggested answers | McKinsey interviewing, Beautify |
| Bain | Written practice cases (Coffee Shop Co., FashionCo.) plus mock interview videos | Bain, Coffee Shop Co. |
| BCG | Case interview guidance and interactive practice materials linked from careers | BCG case prep |
| Deloitte | Interactive practice tools linked from recruiting tips; five-step approach | Deloitte case tips |
Work those prompts out loud. Compare your structure and close to theirs. Do not treat their suggested answers as the only acceptable path — Bain and BCG both state publicly that they care about how you think, not a single right answer.
Firm-specific walkthroughs of how those libraries fit into a recruiting process: Deloitte practice cases, Oliver Wyman practice cases, EY-Parthenon practice cases, Accenture practice cases.
Run one of these today
Take HarborPeak. Close the page. From a blank sheet, restate the prompt, ask three clarifying questions, draw the tree, rebuild the EBIT bridge from memory, and deliver a 60-second close with a number and a risk. Time yourself. If the bridge math takes more than three minutes, drill contribution and percentage change until it does not.
Then sit a full scored case in the same family. CoachNed's library has original profitability and operations cases; everything is open for seven days, no card, then $120 for a recruiting season or $49 a month.
Start with a five-minute typed rep at /start, or an ~18-minute voice case with a seven-score debrief at /interview. For more cases after that, /consulting-cases.
Frequently asked questions
Are these real McKinsey, BCG, or Bain cases?
No. HarborPeak and FrostLine are original teaching examples with invented numbers. For firm-authored samples, use the careers links in the table above. CoachNed is independent and unaffiliated with McKinsey, BCG, Bain, Deloitte, or any other firm named here.
How many case interview examples should I work before first round?
Enough that the five-move sequence is automatic, not enough that you are collecting industries. My estimate: eight to twelve fully worked cases out loud, plus daily short drills, beats forty skimmed PDFs. Quality of the close matters more than headcount of examples.
Should I memorize frameworks from MBA casebooks?
Use MBA club casebooks as prompts — many are free through school clubs — then check the math yourself. Dated "frameworks" in old books are folklore. The interviewer wants a structure built for the prompt in front of you.
What if my math is slow?
Slow clean math with a clear so-what beats fast wrong math. Drill percentages, weighted averages, and break-even until a bridge like HarborPeak's is under three minutes. The /drills/quick-math tool is free forever for that.
Do online chatbot cases replace live examples?
No. Chatbot screens (where used) test structure, exhibit reading, and short written answers under time. Live rounds still reward conversation: clarifying questions, hypothesis updates, and a spoken close. Practice both if your invite includes both.
Sources
- Interviewing at McKinsey — official practice-case index and problem-solving interview description. Checked 2026-09-24.
- Beautify practice case | McKinsey — example of a published interviewer-led case with quantitative questions. Checked 2026-09-24.
- Preparing for the Case Interview | Bain — Bain's written practice cases (Coffee Shop Co., FashionCo.) and interview tips. Checked 2026-09-24.
- Coffee Shop Co. | Bain — sample written practice case on Bain's careers site. Checked 2026-09-24.
- FashionCo. | Bain — sample revenue-decline case with recommendation framing. Checked 2026-09-24.
- Case Interview Preparation | BCG Careers — BCG's description of case interviews and preparation guidance. Checked 2026-09-24.
- Preparing for the Case and Scenario Interview | Deloitte US — Deloitte's five-step case approach and links to prep tools. Checked 2026-09-24.