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

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. Firm-wide hiring statistics and public difficulty scores are useful context, but they blur the differences between consulting, strategy, audit, tax, and regional recruiting. Preparing for the wrong division's format is the fastest way to underperform.

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 strategy arm (formerly Parthenon Group, acquired in 2014). EY-Parthenon works on corporate strategy and PE diligence engagements and often uses more candidate-led case formats than broader EY Consulting. 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.

Framework

EY Interview Process (All Divisions)

1. 01

   Online Application & Screening

   Resume review, then online assessments. The standard battery is a numerical reasoning test (roughly 12 to 15 questions, calculator usually allowed and time-recorded), a verbal reasoning test, and a situational-strengths section of about 16 scenarios. Many regions add the EY Job Simulation, a roughly 1-hour, 6-section exercise that ends with five one-way 'Why EY' video questions.

2. 02

   First Interview Stage

   One or more interviews mixing behavioral questions with a case or scenario discussion. EY Consulting cases are often interviewer-led. EY-Parthenon cases are more likely to be candidate-led.

3. 03

   Later Interview Stage

   Additional behavioral and case interviews. Cases increase in complexity. S&T cases may involve financial data or deal evaluation.

4. 04

   Written Case (EY-Parthenon / some S&T)

   Some offices use an independent data-packet exercise where you analyze exhibits and present findings. This is less common in standard EY Consulting.

5. 05

   Final Round / Superday

   A common shape is three interviews: a behavioral interview, an individual case, and a group case where 3 to 5 candidates analyze a packet for about an hour, present for 15 minutes, and field 15 to 20 minutes of Q&A. Usually led by senior consultants, managers, or partners.

6. 06

   Offer Decision

   Timing varies by office, level, and recruiting channel. Ask your recruiter what decision timeline applies to your process.

That first online stage is a real filter. The EY online assessment battery and Job Simulation screen out many applicants before any interview, so prepare for it as seriously as the cases.

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: Often the most strategy-heavy process. It may include a written case, candidate-led live cases, and group or presentation-style exercises. See the full breakdown in the EY-Parthenon guide.

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

One thing to settle first: published guides disagree on whether EY uses interviewer-led or candidate-led cases. Some prep sites describe EY cases as candidate-led (you drive the analysis like at Bain or BCG), while others describe EY Consulting cases as interviewer-led and structured. Both can be true, because the format depends on the division, the office, and the interviewer. The practical takeaway is to prepare for both styles. If you can only drive an open case but freeze when an interviewer hands you a sequence of guided prompts, you are exposed.

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.

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..." That running thread signals that you are building a single argument, not reacting to disconnected prompts.

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 roughly 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

Some EY final rounds include a group case exercise: 3 to 5 candidates receive a data packet, get about an hour to analyze it and build a recommendation, present for around 15 minutes, then take 15 to 20 minutes of Q&A while senior staff observe. In a related variant, the written case, some offices send the materials roughly 48 hours ahead so you arrive with slides already prepared. Either way, this is not just 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

Checklist

Execution checklist

• Identify which EY division you are targeting

  EY Consulting, S&T, and Parthenon use different case formats. Preparing for the wrong one wastes time.

• Practice 8-10 interviewer-led cases

  EY Consulting and S&T primarily use interviewer-led formats. You need to excel at structured responses, not just open-ended analysis.

• Review basic valuation concepts (multiples, synergies, DCF logic)

  S&T and Parthenon cases frequently involve acquisition evaluation. You cannot fake financial intuition.

• Prepare your 'Why EY?' answer with division-specific detail

  Generic answers about consulting are immediately obvious. Reference the specific practice area and type of work.

• Run at least 1 group case simulation

  Group cases appear in some later-stage EY processes and test collaboration, not just analysis

• Read 10-15 Glassdoor interview reviews for your target division

  Candidate reports reveal specific case types, behavioral question patterns, and interviewer expectations by office and level

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 only for broad Big 4 consulting cases when Parthenon often expects strategy-style casing. 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

Related Guides

• EY-Parthenon case interview guide: deep dive on EY's strategy arm, written case, and PE-focused prep
• EY Launch internship program: EY's early-career and student leadership pipeline into full-time consulting roles
• Deloitte case interview guide: Big 4 peer with a comparable interview format
• KPMG case interview guide: Big 4 peer comparison for candidates applying across firms
• PwC case interview guide: Big 4 peer including written case and group formats
• 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
• EY cover letter guide: how to tailor your application letter to EY's practices and values before the interview stage
• See where EY's divisions fit among the main types of consulting firms: how Big 4 advisory, deal, and strategy arms compare

Sources and Further Reading (checked June 18, 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/
• My Consulting Offer, EY Online Assessment and Job Simulation: https://www.myconsultingoffer.org/case-study-interview-prep/ey-online-assessment/
• IGotAnOffer, EY-Parthenon Case Interview: https://igotanoffer.com/blogs/mckinsey-case-interview-blog/ey-parthenon-case-interview
• 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
• 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/