Most candidates rehearse EY-Parthenon cases as strategy cases with a private-equity sticker on top. That is the wrong drill. The interviewer is not scoring whether you can name market attractiveness; they are scoring whether you will take a position on capital at a specific price.
The thesis is simple: an EY-Parthenon practice case is finished only when you can defend buy, walk, or buy-at-a-different-multiple with arithmetic attached. After this page you will have a diligence spine you can open in sixty seconds, a closed set of transaction math to rep, one fully worked commercial-due-diligence mini-case with an exhibit, and a self-score for whether your close actually closes.
CoachNed is not affiliated with EY or EY-Parthenon. Confirm formats with your invitation; offices vary.
What EY-Parthenon sells, and why that changes your practice mix
EY-Parthenon markets itself as transformative strategy and transactions: strategy work that sits next to deals, valuation, and capital decisions rather than floating above them (EY-Parthenon overview). Commercial due diligence, on EY's own diligence page, is defined as a detailed look at a target's market, customers, and competitive position, plus growth potential and risk (EY due diligence services). That definition is already a case outline.
The institutional history matters for how the room feels. EY combined with The Parthenon Group in 2014, folding a strategy boutique known for private-equity and investment-strategy work into EY's transaction advisory side (EY completes combination with The Parthenon Group). You are not interviewing for a pure operations shop. You are interviewing for a firm that still earns fees answering "should we put money in this asset at this price?"
US campus recruiting for the Strategy Consultant Program is explicit about format at a high level: selected applicants face a mix of behavioral and case-based interviews with multiple EY-Parthenon professionals, with offers typically within a week (EY-Parthenon Strategy Consultant Program). Written cases, group cases, and assessment-centre extras show up in candidate folklore and some invitations; treat them as confirm-with-recruiter, not as universal defaults.
| Practice habit | What it trains | What EYP actually rewards |
|---|---|---|
| Profitability trees with PE labels | Cost and revenue drivers | Useful mid-case, weak as a close |
| Market-sizing only | Comfort with big numbers | Necessary, not sufficient |
| Diagnosis then "risks" | Coverage | Sounds unfinished |
| Price, growth path, exit, return | Investor judgment | The differentiating close |
Shift roughly half your reps to prompts where a buyer is deciding something. Force a multiple or a dollar figure into every final sentence.
The diligence spine: market, asset, deal
I stop listening when a candidate opens an acquisition case with "I'd look at revenues, costs, and other." That tree is for a margin case. A diligence case needs three peer branches you can test in order.
1. Market. Size, growth, structure, and where the margin pool sits. A large market growing at seven percent with five consolidating players is a different investment from the same growth rate with four hundred fragmented operators. Fragmentation often supports a roll-up thesis; concentration often does not.
2. Asset. Share trajectory, customer stickiness, channel dependence, switching costs. Ask for cohort or retention evidence before you ask for another market chart. Thirty percent growth bought with paid acquisition is not the same asset as fifteen percent growth on retention.
3. Deal. Entry multiple, the growth and margin path implied by that multiple, and the exit assumption. If you never touch the asking price, you wrote a market study.
Kill deals early. If the market is shrinking, you do not need the cohort analysis. Request evidence in that order because the first block is cheapest to test.
Ned's rule. If your closing sentence does not contain a multiple, a dollar price, or an explicit condition that changes one of those, you have not finished an EY-Parthenon-style case. "Attractive market with risks" is a diagnosis, not a recommendation.
The math set you should own cold
Transaction cases recycle a small set of calculations. Own these four families before you invent frameworks.
| Family | Core calculation | How it shows up in the room |
|---|---|---|
| Multiples | Enterprise value / EBITDA | "They want 12x on $28M. What is the ask?" |
| Growth | Forward and reverse CAGR | "Revenue from $140M to $230M in five years. What rate?" |
| Returns | Money multiple, then a rough annual return | "You get 2.0x in five years. Is that enough?" |
| Bridges | EBITDA walk across volume, price, mix, cost | "Margin fell three points. Show me the three." |
Three approximations worth memorizing: doubling over five years is about fifteen percent a year; tripling over five years is about twenty-five percent; a 1.6x money multiple over five years is roughly nine percent a year. The reverse question is asked more often than the forward one: given entry price, exit multiple, and a return bar, what growth must the asset deliver? That is the question that turns description into a decision.
Worked mini-case: HarborSeal warehouse SaaS (buy-side CDD)
This scenario is original. It is not an official EY-Parthenon case. Cover the worked close, write your own structure and math, then compare.
Prompt. Mid-market fund Apex Ridge is diligenceing HarborSeal, a warehouse-management SaaS vendor. HarborSeal does $95M in annual recurring revenue at a 22% EBITDA margin. The seller wants 14x EBITDA. Apex Ridge underwrites to at least a 2.2x money multiple over five years and assumes it can exit at 12x. Should Apex Ridge buy?
Structure (spoken in under a minute). I would test three branches. First, is the US mid-market WMS market large and growing enough to support double-digit ARR growth without heroic share gains? Second, can HarborSeal hold or gain position — net retention, customer concentration, switching costs versus Blue Yonder and Manhattan peers? Third, does 14x on today's EBITDA clear a 2.2x money multiple if we exit at 12x, and if not, what growth path or entry multiple would?
Exhibit 1 — HarborSeal operating snapshot (invented, internally consistent).
| Metric | Year 0 | Notes |
|---|---|---|
| ARR | $95M | 78% subscription, 22% implementation |
| EBITDA margin | 22% | EBITDA = $20.9M |
| Asking multiple | 14x | Implied EV = $292.6M |
| Net revenue retention | 108% | Flat for two years |
| Top-10 customer share | 31% | Two logistics 3PLs at 9% and 7% |
| US mid-market WMS TAM | $3.8B | Growing ~9% / year (brief assumption) |
| HarborSeal share | ~2.5% | Share roughly flat |
Math.
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Entry. EBITDA = $95M x 22% = $20.9M. At 14x, ask = $20.9M x 14 = about $293M.
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Base-case exit. Assume ARR compounds at 12% (modestly above a 9% market on slight mix shift), so Year-5 ARR = $95M x (1.12)^5. (1.12)^5 is about 1.76, so ARR ~ $167M. Assume margin expands to 26% on scale, so Year-5 EBITDA ~ $43.4M. Exit at 12x = $521M.
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Return. $521M / $293M = about 1.8x over five years. That is below the 2.2x bar. Rough annual return on 1.8x in five years is low teens, not the mid-to-high teens the fund is underwriting.
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Reverse the hurdle. To clear 2.2x on a $293M entry, exit EV must be about $644M. At a 12x exit that requires ~$53.7M of EBITDA. From $20.9M, that is roughly a 21% CAGR in EBITDA for five years. In a market growing at 9%, that path needs either sustained share gains or a roll-up that the brief does not yet support. Flat 2.5% share and 108% NRR do not justify it.
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Price that works. Holding the base path (exit EV ~$521M) and requiring 2.2x back-solves an entry of about $237M, or roughly 11.3x on $20.9M EBITDA. Call it 11x to 11.5x as the walk-up zone.
Recommendation. Walk at 14x. The price implies EBITDA growth roughly double the market without a proven share or M&A mechanism. Reopen at about 11x to 11.5x, or at 14x only if diligence proves a contracted tuck-in pipeline that adds at least ~$8M to $10M of Year-5 EBITDA beyond the organic case. The finding that would flip me: net retention above ~115% with top-10 concentration falling below 20%, because that supports both a higher growth path and a stronger exit multiple.
If your version of this case ended with "attractive SaaS market, watch customer concentration," the structure was fine and the ending was not.
How to score your own close
After every practice case, mark yourself against this sheet. Be harsh.
| Score item | Pass | Fail |
|---|---|---|
| Decision | Buy / walk / buy-at-X in the first sentence | "It depends" without a number |
| Price link | Multiple or EV named | Market commentary only |
| Math chain | Entry, path, exit, return connected | Isolated CAGR or isolated multiple |
| Kill criteria | One finding that would flip you | Generic risk list |
| Evidence order | Market before asset before deal | Deal math before market is alive |
In a typical first round of eight candidates, my estimate is that two or three reach a priced close under pressure. The rest leak points on the last ninety seconds, not on the opening tree.
Written and group formats: triage, not coverage
Neither exercise is universal. Both appear in invitations and candidate reports, more often in European assessment centres than as a US default. Confirm on your email.
For a written pack, decide the decision sentence before you read exhibits. Triage into must-read, maybe, and ignore. Most packs have three or four decisive exhibits and a long tail of context. Build the deck backwards from the answer slide. Time spent reading everything is time stolen from the recommendation.
For a group case, observers are not scoring airtime. Contribution quality, whether you moved the group forward, and whether you improved someone else's point are what get written down. Take the timekeeping job early, restate the question when the group drifts, and hand a specific analysis ask to the quietest person.
Practice this today
Run one diligence case end to end with a hard rule: your final sentence must include a multiple. Use the HarborSeal numbers above, or open a live voice case on CoachNed and force the same close discipline on whatever prompt you draw (live interview with Ned). If the arithmetic is the bottleneck, grind the math drill first (quick math is free forever; the graded math drill is in the seven-day open window). Everything on CoachNed is open for seven days with no card; then $120 for a recruiting season or $49 a month.
When you want more transaction-shaped prompts, the case library and the PE case interview guide sit next to this page. For process, rounds, and what changes versus EY Consulting, use the EY-Parthenon case interview guide.
Frequently asked questions
Are EY-Parthenon cases mostly commercial due diligence?
Many are transaction-flavored — buy-side or sell-side diligence, growth under ownership, market entry tied to a deal thesis — because that is a large share of what the firm sells. You will still see classic strategy prompts. Prep the diligence spine and the math set; do not ignore profitability and market-sizing entirely.
Do I need a written case for every EY-Parthenon office?
No. The firm publishes a behavioral-plus-case mix for US Strategy Consultant recruiting and leaves local extras to the invitation. Treat written and group formats as possible, not guaranteed.
What money multiple should I assume in practice cases?
Use whatever the prompt states. If none is given, state your assumption out loud — for mid-market PE, a 2.0x to 2.5x money multiple over five years is a common practice bar, not a firm rule. Label it as your assumption so the interviewer can adjust it.
How is EY-Parthenon different from Bain or L.E.K. in practice cases?
All three will punish a soft close. EY-Parthenon's published positioning leans harder into strategy-plus-transactions, so price, multiple, and return show up more often than in a pure corporate-strategy practice set. The mechanics of a clean recommendation still transfer.
Should I memorize EY's commercial due diligence definition?
Memorize the four ideas — market, customers, competitive position, growth and risk — then turn them into your own spoken branches. Quoting marketing copy does not score; using the logic does.
Sources
- EY-Parthenon: Transformative Strategy and Transactions — firm positioning of strategy with transactions. Checked 2026-09-24.
- Due Diligence for Informed Decisions and Sustainable Growth | EY - US — official commercial due diligence definition (market, customers, competitive positioning, growth, risk). Checked 2026-09-24.
- EY-Parthenon Strategy: Consultant Program | EY - US — published US interview mix (behavioral and case-based) and offer timing. Checked 2026-09-24.
- EY completes combination with The Parthenon Group — September 2014 combination closing, PE and investment-strategy heritage. Checked 2026-09-24.
- Careers in EY-Parthenon Strategy, Transactions, Corporate Finance — careers framing around investor mindset and transformative growth. Checked 2026-09-24.