EY Case Interview: Format by Division, Sample Cases, and Prep Strategy (2026)

EY received 5.1 million applications in 2024 and hired roughly 97,000 people — a 5% acceptance rate. But "EY" is not one interview. EY Consulting, EY Strategy & Transactions, and EY-Parthenon each run distinct case formats, evaluate different skills, and attract different candidate pools. Glassdoor rates EY interviews at 2.9/5 difficulty overall, but that average hides a range: EY Consulting sits at 2.6/5 while EY-Parthenon hits 3.3/5, on par with McKinsey. Preparing for the wrong division's format is the fastest way to get cut.

EY's Three Consulting Divisions: What Each Actually Does

Before preparing for a case, you need to know which EY you are interviewing for. The three divisions share a brand but operate with different mandates, clients, and cultures.

EY Consulting is EY's largest advisory practice. The work centers on technology implementation, performance improvement, cybersecurity, supply chain transformation, and operational advisory. Think SAP migrations, cloud architecture, or redesigning a client's operating model. Cases in this division test whether you can structure a practical business problem and reason through implementation trade-offs.

EY Strategy & Transactions (S&T) handles deal-oriented work — M&A advisory, commercial due diligence, valuations and modeling, and restructuring. S&T sits closer to investment banking in some respects, though the strategic angle differentiates it. Cases here test financial reasoning, deal logic, and your ability to evaluate whether an acquisition creates value.

EY-Parthenon is EY's pure strategy arm — formerly Parthenon Group, acquired in 2014. EY-Parthenon competes directly with McKinsey, BCG, and Bain on corporate strategy and PE diligence engagements. Their cases are candidate-led and MBB-level in difficulty. For a deep dive on this division specifically, read the EY-Parthenon case interview guide.

The EY Interview Process: Stage by Stage

The process is broadly consistent across divisions, with some variation. Here is the standard structure for EY Consulting, with notes on how S&T and Parthenon differ.

Key differences by division:

• EY Consulting: Emphasizes behavioral questions heavily. The case component is shorter and more structured than at Parthenon. Expect scenario-based questions like "A client's IT migration is 6 months behind schedule — how would you diagnose and address the delay?"
• EY S&T: Cases lean financial — expect questions about whether an acquisition target is fairly valued, or how to structure a divestiture. Basic financial modeling intuition is expected.
• EY-Parthenon: The most intensive process. Includes a written case, candidate-led live cases, and often a group case. See the full breakdown in the EY-Parthenon guide.

EY Consulting Case Format: What the Interviewer-Led Style Looks Like

In an interviewer-led EY Consulting case, the interviewer controls the pace. They present a problem, then walk you through a series of questions — each building on the last. You do not need to structure the entire case yourself; instead, you respond to each prompt with clear, structured thinking.

Typical EY Consulting case flow:

1. Prompt: "Our client is a mid-size hospital system experiencing a 15% increase in patient wait times over the past year. What might be driving this?"
2. Follow-up: "We've identified that the bottleneck is in the discharge process. What factors could slow discharge?"
3. Data question: "Here's a table showing average discharge times by department. What do you notice?"
4. Recommendation: "Given your analysis, what would you recommend the client do?"

This is different from a candidate-led case where you would receive the prompt and drive the entire analysis. The interviewer-led format tests your ability to think on your feet within a guided structure, communicate clearly at each step, and handle data when it arrives.

Based on 300+ practice sessions on Road to Offer, the most common mistake in interviewer-led cases is passivity — answering each question in isolation without connecting the pieces. Strong candidates reference earlier answers when responding to new prompts: "This connects to the staffing data we looked at earlier, which showed..."

EY S&T Case Format: Deal-Oriented Thinking

Strategy & Transactions cases test whether you can evaluate a business decision through a financial and strategic lens. These cases sit between the operational focus of EY Consulting and the pure strategy focus of EY-Parthenon.

Common S&T case types:

• Should our client acquire this target? At what price?
• A PE fund is evaluating a portfolio company — what are the value creation levers?
• The client is considering divesting a business unit. Should they?
• Restructuring: the client is overleveraged — what are the options?

What S&T interviewers evaluate:

• Can you assess whether a deal creates value?
• Do you understand basic valuation concepts (multiples, DCF logic, synergies)?
• Can you identify risks in a transaction?
• Do you connect financial analysis to strategic rationale?

You do not need investment banking-level modeling skills. But you should be comfortable with EBITDA multiples, revenue synergy logic, and the difference between strategic and financial buyers. Review the profitability framework for the financial decomposition skills that transfer directly to S&T cases.

Worked Case Example: EY Consulting — Operations Improvement

Prompt: "Our client is a national logistics company. On-time delivery rates have dropped from 94% to 87% over the past 18 months, and their largest customer (30% of revenue) is threatening to switch providers. How would you diagnose and fix this?"

Step 1 — Structure the diagnosis: "I'd break the on-time delivery problem into three areas: network capacity — are there bottleneck routes or hubs? Operational execution — are drivers, vehicles, or scheduling systems underperforming? And demand changes — has volume or delivery mix shifted in a way the network wasn't built for?"

Step 2 — Interviewer provides data: The interviewer shares that total delivery volume grew 22% over 18 months, but fleet size only grew 8%. Average route load factor increased from 78% to 93%.

Step 3 — Quantitative analysis:

• Volume growth: +22%
• Fleet growth: +8%
• Effective capacity gap: 22% - 8% = 14 percentage points of unmet demand growth
• Load factor at 93% means the network is running near-maximum — delays are inevitable at peak

"The root cause is clear: demand grew faster than fleet capacity. A 93% load factor leaves almost no buffer for disruptions. Every delayed pickup cascades across the route."

Step 4 — Recommendation: "I'd recommend a two-phase approach. Immediately: renegotiate the delivery windows for the largest customer to reduce peak-hour pressure — this protects the 30% revenue relationship while buying time. Within 6 months: expand the fleet by 15-18% through a mix of owned vehicles and contracted carriers, targeting the 5 highest-volume routes first. The investment should be $8-12M but protects roughly $45M in at-risk revenue from the largest customer alone. The ROI case is straightforward."

Worked Case Example: EY S&T — Acquisition Evaluation

Prompt: "A PE fund is considering acquiring a regional chain of 28 veterinary clinics for $120M. Should they proceed?"

Structure: "I'd evaluate this across three areas: market attractiveness of the veterinary services industry, competitive position of the target, and financial return at $120M."

Key analysis (with numbers):

The interviewer shares: the 28 clinics generate $5.2M average revenue each ($145.6M total), EBITDA margins are 20%, the vet services market is growing at 9% annually, and the top 5 national consolidators hold only 15% market share.

• Total EBITDA: $145.6M x 20% = $29.1M
• Implied multiple: $120M / $29.1M = 4.1x EBITDA
• Market growth: 9% annually — well above GDP
• Fragmentation: top 5 hold only 15% — significant consolidation opportunity

"At 4.1x EBITDA in a 9%-growth, highly fragmented market, the entry valuation looks attractive. Comparable vet clinic transactions have closed at 8-12x EBITDA for scaled platforms. If the fund can add 10-15 clinics through tuck-in acquisitions and improve margins through shared procurement, there's a realistic path to a 3x return on a 5-year hold."

Recommendation: "Proceed to detailed diligence, focused on two questions: what is the vet turnover rate at these clinics (the #1 risk to revenue stability), and are there 10+ acquisition targets within the geographic footprint for platform expansion?"

Behavioral Questions Across EY Divisions

All three EY divisions weight behavioral questions heavily. EY's culture emphasizes collaboration, client service, and integrity — and interviewers test for these directly.

Frequently asked EY behavioral questions:

• "Tell me about a time you had to work with a difficult team member."
• "Describe a situation where you had to deliver bad news to a client or stakeholder."
• "Give an example of when you had to learn something quickly to solve a problem."
• "Why EY specifically — and which service line interests you most?"

The last question is where most candidates fail. Saying "I want to do consulting" is not enough. You must specify the division and articulate why. "I'm drawn to EY's Strategy & Transactions practice because I want to evaluate deals from a strategic angle — not just run models. The combination of commercial diligence and strategic assessment is what differentiates S&T from pure banking."

For a complete behavioral prep guide, see behavioral interview consulting and case interview fit questions.

The Group Case Exercise: How to Stand Out

Most EY final rounds include a group case exercise — 3-5 candidates receive a data packet and collaborate for 60-75 minutes before presenting a recommendation to a panel. This is not a case interview; it is a teamwork assessment disguised as a case.

What evaluators score:

• Do you contribute analytical insights (not just opinions)?
• Do you build on others' ideas rather than competing?
• Can you disagree constructively without shutting others down?
• Do you help the group stay on track when time runs low?

Tactical advice:

• Volunteer to structure the initial approach, but do not dominate the conversation
• When another candidate makes a good point, explicitly say "I think that's right, and it connects to..." — evaluators notice collaboration signals
• Track time for the group — "We have 20 minutes left, and we haven't discussed risks yet" — this is a leadership signal that does not require arguing

4-Week EY Case Interview Prep Plan

Common Mistakes by Division

EY Consulting applicants:

• Preparing for candidate-led cases when EY Consulting uses interviewer-led format — you end up over-structuring and under-responding
• Ignoring the technology and implementation angle — EY Consulting cases are practical, not abstract strategy
• Weak behavioral answers — EY Consulting weights culture fit as heavily as analytical skill

EY S&T applicants:

• Not understanding basic deal mechanics — if you cannot calculate an EBITDA multiple or explain revenue synergies, S&T is the wrong division
• Treating S&T cases like banking technicals — they want strategic reasoning, not just financial modeling
• Confusing S&T with Parthenon — S&T handles deal execution while Parthenon handles pure strategy

EY-Parthenon applicants:

• Preparing for Big 4 difficulty when Parthenon operates at MBB level — see the full EY-Parthenon case interview guide for specific prep
• Skipping written case practice — the 60-90 minute data packet exercise catches unprepared candidates
• Generic "Why EY" answers that do not reference Parthenon's PE practice or strategy focus

Test Your Knowledge

Related Guides

• EY-Parthenon case interview guide — deep dive on EY's strategy arm, written case, and PE-focused prep
• Case interview frameworks complete guide — how to build structures for any case type
• Profitability framework — financial decomposition skills that transfer to S&T and Parthenon cases
• Behavioral interview consulting — STAR method and fit question preparation
• Case interview fit questions — the most common behavioral questions across Big 4 firms
• Consulting career path — understand EY's career progression to answer "Where do you see yourself?" questions
• Market entry framework — a core framework for EY-Parthenon and S&T cases

Sources and Further Reading (checked April 8, 2026)

• Management Consulted, EY Interview Guide: https://managementconsulted.com/ey-interview/
• MConsultingPrep, EY Case Interview: https://mconsultingprep.com/ey-case-interview
• My Consulting Offer, EY Case Interview: https://www.myconsultingoffer.org/case-study-interview-prep/ey-case-interview-parthenon/
• Glassdoor, EY Interview Questions: https://www.glassdoor.com/Interview/EY-Interview-Questions-E2784.htm
• Glassdoor, EY Consulting Interview Questions: https://www.glassdoor.com/Interview/EY-Consulting-Interview-Questions-EI_IE2784.0,2_KO3,13.htm
• The Cambridge Consultant, EY Acceptance Rate: https://thecambridgeconsultant.com/ernst-amp-young-acceptance-rate/
• EY Careers FAQ: https://www.ey.com/en_us/careers/frequently-asked-questions
• Umbrex, EY Consulting Profile: https://umbrex.com/resources/profiles-of-the-top-consulting-firms/overview-profile-history-ey-consulting/