Author: Taylor Warfield, Former Bain Manager and interviewer

Last Updated: May 19, 2026

 

The EY-Parthenon Strategy case interview tests your ability to think like an investor under time pressure. Cases focus heavily on private equity, commercial due diligence, market entry, and growth strategy. By the end of this article, you will know exactly how the Strategy interview process works and how to pass each round.

 

But first, a quick heads up:

 

McKinsey, BCG, Bain, and other top firms accept less than 1% of applicants every year. If you want to triple your chances of landing interviews and 8x your chances of passing them, watch my free 40-minute training.

 

What Is the EY-Parthenon Strategy Case Interview?

 

The EY-Parthenon Strategy case interview is a candidate-led problem-solving exercise that tests your ability to structure an ambiguous business problem, run quick financial math, and deliver an investor-grade recommendation in 30 to 60 minutes. Cases focus on commercial due diligence, market entry, growth strategy, M&A, and value creation. Compared to MBB cases, EY-Parthenon cases move faster and require sharper financial intuition.

 

EY-Parthenon is the strategy and transactions arm of Ernst & Young, with more than 25,000 professionals across 120+ countries. The practice grew out of EY's 2014 acquisition of The Parthenon Group, a boutique strategy firm founded in 1991 by two former Bain consultants. The Strategy practice generated more than $3 billion in revenue in 2025 and remains one of the largest non-MBB strategy houses globally.

 

The Strategy case interview differs from a generic Big 4 case in three important ways. First, the math is faster and more finance-flavored, with frequent use of IRR, payback period, and EBITDA multiples. Second, you will often be asked to take an investor's perspective rather than a corporate planner's perspective. Third, structured commercial thinking matters more than memorized frameworks.

 

How Is EY-Parthenon Strategy Different from EY Advisory?

 

EY-Parthenon Strategy and EY Advisory are two separate consulting tracks inside EY, and the case interviews differ significantly. Strategy cases focus on commercial due diligence, market entry, growth, and value creation. Advisory cases focus on technology implementation, operations, and risk transformation.

 

This distinction matters because the cases you will face depend entirely on which group you applied to. A candidate interviewing for the Strategy team will rarely see a technology implementation case. A candidate interviewing for EY Advisory will rarely see a commercial due diligence case.

 

Here is a side-by-side comparison of how the two practices differ:

 

Dimension	EY-Parthenon Strategy	EY Advisory
Project types	M&A, commercial due diligence, growth strategy, market entry, turnaround	Technology implementation, operations, risk, transformation
Case style	Investor-led, fast-paced, financially intense	Process and implementation focused
Common industries	Private equity, healthcare, consumer, tech	Banking, insurance, government, retail
Math difficulty	High (CAGR, IRR, payback, margin analysis)	Moderate (ROI, cost savings, throughput)
Closest comparison	MBB and L.E.K.	Deloitte and Accenture

 

Knowing which track you applied to is the single biggest factor in how you should prepare. Confirm with your recruiter before you start any case prep. Roughly 60% of EY-Parthenon Strategy cases involve a private equity angle, while Advisory cases rarely involve PE at all.

 

What Does the EY-Parthenon Strategy Interview Process Look Like?

 

The EY-Parthenon Strategy interview process has two to three rounds and takes 4 to 8 weeks from first application to offer. The process includes an online screening, one or two first-round case and fit interviews, and a final round that often includes a group case or written case.

 

Here is the standard sequence and what to expect at each step.

 

Round 1: Application screening and online assessment

 

The application screening starts with your resume and cover letter. If accepted, you will usually take EY's online numerical and logical reasoning assessment within a week. Some offices also include a short pre-recorded video interview with motivation questions.

 

The numerical reasoning portion lasts about 20 to 25 minutes and tests your ability to interpret charts and tables under time pressure. It is not advanced math. It is speed and accuracy on simple calculations.

 

The video interview, when it appears, asks 3 to 5 questions like "Why EY-Parthenon?" or "Tell me about a time you led a team." You typically have 60 seconds to think and 2 minutes to answer.

 

Round 2: First round case and fit interviews

 

The first round consists of one or two 45 to 60 minute interviews, typically with consultants or managers. Each interview combines a short fit portion with one full case. Cases at this stage focus on structured thinking, basic financial math, and clear communication.

 

First round cases are usually market entry, profitability, or simple growth strategy questions. Interviewers want to see that you can build a clean framework, do basic math without errors, and reach a defendable recommendation. Roughly 30% of first-round candidates advance to the final round.

 

Round 3: Final round or Super Day

 

The final round includes two to four interviews with senior managers or partners. Many offices include a group case interview or a written and slide-based case alongside the live cases. Final round cases are faster, harder, and often investment-flavored.

 

Some offices run the entire final round as a single Super Day, combining a written case in the morning with two live cases and a group exercise in the afternoon. Confirm the exact format with your recruiter at least one week before the interview. Final round offer rates run roughly 30% to 40% across regions.

 

Here is a quick comparison of how the rounds differ:

 

Round	Format	Length	Interviewer	Focus
1	Online assessment	30-40 min	Automated + recruiter	Numerical reasoning, basic fit
2	1-2 live case and fit	45-60 min each	Consultant or Manager	Structure, math, communication
3	2-4 live, group, or written	45-60 min each	Manager or Partner	Investor judgment, leadership, fit

 

What Types of Cases Does EY-Parthenon Strategy Use?

 

EY-Parthenon Strategy uses six main types of cases: commercial due diligence, market entry, growth strategy, M&A, profitability, and market sizing. Roughly 60% of Strategy cases are private equity or transactions-flavored, which makes commercial due diligence the single most common case type.

 

Commercial due diligence cases

 

Commercial due diligence cases ask you to evaluate a target company on behalf of a private equity investor. You will need to assess the market, the competitive position of the target, the financials, and the key risks. The recommendation is binary: should the PE firm invest or walk away?

 

Example: A mid-market PE fund is considering a $400M buyout of a regional premium pet food company. Should they invest? You will need to look at market growth, customer retention, competitive moats, and the target's ability to hit its forecasted EBITDA.

 

Commercial due diligence cases are the most common case type at EY-Parthenon Strategy and account for roughly 40% of cases reported by candidates. Practice at least 10 of these before your interview.

 

Market entry cases

 

EY-Parthenon market entry cases ask whether a company should enter a new geography, product category, or customer segment. These cases almost always include a quantitative market sizing component. They also expect a clear go-to-market recommendation by year 1, year 3, and year 5.

 

Example: A US fast-casual restaurant chain with 150 stores is considering expansion into the UK. Should they enter, and if so, what entry strategy should they use?

 

Growth strategy cases

 

Growth strategy cases focus on how to accelerate revenue or earnings for an existing business. These cases test your ability to identify and prioritize growth levers like pricing, mix, new products, geographic expansion, and customer acquisition.

 

Example: A horizontal SaaS company has hit $200M in annual recurring revenue, and growth has slowed from 40% to 12% year over year. What should they do to reaccelerate growth to 25%?

 

M&A cases

 

M&A cases ask you to evaluate a potential merger or acquisition. You will need to assess strategic fit, financial impact, integration risks, and synergy potential. EY-Parthenon's M&A cases often include a quick back-of-the-envelope valuation using EBITDA multiples or DCF.

 

Example: A large traditional insurance carrier is considering acquiring a digital insurance startup for $1.2B. The target has $80M in revenue and is growing 60% annually. Should the carrier proceed?

 

Profitability and cost reduction cases

 

Profitability cases ask you to diagnose declining margins and propose fixes. Cost reduction cases ask you to find a specific dollar amount of savings, often 20% to 30% of the cost base. Both case types are common at the first round.

 

Example: A regional grocery chain with 80 stores has seen operating margin fall from 4.2% to 2.1% over three years. What is driving the decline and what should they do?

 

Market sizing cases

 

Market sizing cases ask you to estimate the size of a market, customer base, or revenue opportunity. EY-Parthenon often embeds market sizing inside a larger case rather than asking it standalone. The sizing portion typically takes 5 to 10 minutes.

 

Example: Estimate the annual global market for at-home rapid diagnostic test kits in dollars.

 

How Do You Solve an EY-Parthenon Strategy Case Interview?

 

There are six steps to solve any EY-Parthenon Strategy case interview. The same approach works for commercial due diligence, market entry, growth, M&A, profitability, and market sizing cases.

 

Step 1: Understand the case

 

The interviewer will start by giving you a short case prompt, usually 1 to 3 sentences. Take notes on the company, the industry, the objective, and any numbers mentioned. Do not start brainstorming yet.

 

Read the prompt back to confirm you heard it correctly. Many candidates lose points in the first minute by missing a key detail like the time horizon or the geography.

 

Step 2: Ask clarifying questions

 

You should ask two or three sharp clarifying questions before doing anything else. The most useful questions are about the objective, the time horizon, and any constraints. Do not ask questions that the interviewer will obviously answer later in the case.

 

For a commercial due diligence case, useful clarifying questions include: What is the investor's hold period? What return are they targeting? What is the deal thesis?

 

Step 3: Build a tailored framework

 

Take 60 to 90 seconds of silence to build a tailored framework. Avoid memorized frameworks because EY-Parthenon interviewers can spot them immediately.

 

The best case interview frameworks have three or four top-level buckets that fully cover the case objective. For a CDD case, a strong framework would include market attractiveness, target company position, financial upside, and key risks. For a market entry case, the framework should cover market size and growth, competitive intensity, company fit, and financial viability.

 

Step 4: State a hypothesis

 

After walking the interviewer through your framework, state your initial hypothesis. A hypothesis is an educated guess at the answer based on what you know so far. It is fine for the hypothesis to be wrong because you will refine it as you learn more.

 

For a CDD case, your hypothesis might be: "Based on what we know, I would lean toward recommending the investment, but I want to pressure test market growth and customer retention before I commit."

 

Step 5: Test your hypothesis with analysis

 

The bulk of the case is spent testing the hypothesis through quantitative and qualitative analysis. You will work through your framework branch by branch, asking for data, doing math, and refining your view. Always tie each piece of analysis back to your hypothesis.

 

EY-Parthenon expects you to drive the case forward. If you wait for the interviewer to feed you the next step, you will lose points fast.

 

Step 6: Deliver a recommendation

 

End with a clear, structured recommendation. State your answer in the first sentence, give two or three reasons supporting it, name one or two risks, and propose next steps. The whole recommendation should take 60 to 90 seconds.

 

For a CDD case, a strong recommendation sounds like: "Yes, the PE fund should invest. The market is growing at 8% annually, the target has 30 points of margin advantage over peers, and the financial returns clear the 25% IRR hurdle. The main risks are customer concentration and regulatory exposure. As next steps, I would do operational due diligence and reference 10 of the top customers."

 

What Are 8 Example EY-Parthenon Strategy Case Interviews?

 

Below are eight example cases reported by recent EY-Parthenon Strategy candidates. Use them to identify case types you struggle with and to build a practice plan.

 

Example 1: PE due diligence on a pet food company

 

A mid-market private equity fund is considering a $400M buyout of a regional premium pet food company. The fund targets a 3x return over 5 years. Should they invest?

 

Example 2: Market entry for a fast-casual chain

 

A US fast-casual restaurant chain with 150 stores is considering entry into the UK market. Recommend whether they should enter, and if so, propose an entry strategy and store count target by year 5.

 

Example 3: Growth strategy for a SaaS company

 

A horizontal SaaS company has hit $200M in ARR. Growth has slowed from 40% to 12% year over year. Recommend a growth strategy to reaccelerate to 25% annual growth.

 

Example 4: M&A in insurance technology

 

A large traditional insurance carrier is considering acquiring a digital insurance startup for $1.2B. The target has $80M in revenue and is growing 60% annually. Should the carrier proceed?

 

Example 5: Profitability for a regional grocery chain

 

A regional grocery chain with 80 stores has seen operating margin decline from 4.2% to 2.1% over three years. Diagnose the cause and recommend specific actions to restore margin.

 

Example 6: Market sizing for at-home diagnostic kits

 

Estimate the annual global market for at-home rapid diagnostic test kits in dollars. Then identify the most attractive geographic markets to enter.

 

Example 7: Turnaround for an underperforming media business

 

A PE fund owns a regional media business that has missed its budget for six quarters in a row. EBITDA is down 35% versus the deal model. Recommend a turnaround plan to recover lost value.

 

Example 8: Portfolio strategy for a diversified industrial

 

A diversified industrial company has eight business units across four end markets. The board wants to know which units to invest in, which to harvest, and which to divest.

 

How Should You Prepare for the EY-Parthenon Strategy Group Case?

 

The EY-Parthenon Strategy group case interview is a 60 to 75 minute exercise where you work in a team of 3 to 5 candidates to analyze a case and present a recommendation. Interviewers observe rather than participate. Your goal is to add value to the group without dominating the conversation.

 

Here is how the group case typically runs:

 

• You will be given a packet of 10 to 20 pages of case materials

 

• Your group has 60 to 75 minutes to read the materials, discuss, and prepare slides

 

• The group presents the recommendation for 15 minutes

 

• Interviewers ask 10 to 15 minutes of follow-up questions

 

• Each candidate is evaluated individually on contribution and behavior

 

There are five ways to add value during a group case:

 

• Lead or guide the discussion by proposing structure, topics, and time allocation

 

• Build on other people's ideas instead of pushing your own at every turn

 

• Synthesize and summarize where the group is making progress

 

• Track time and prompt the group when it is falling behind

 

• Pull in quieter teammates by asking for their thoughts

 

Treat your group as teammates, not as competition. Multiple people in the same group routinely receive offers, so making your teammates look good often makes you look good. Roughly 40% of group case candidates advance to receive an offer.

 

What Are the Top 7 Tips for the EY-Parthenon Strategy Case Interview?

 

The following seven tips will give you the biggest improvement in your EY-Parthenon Strategy case interview performance. Each one is based on patterns I have seen across hundreds of coached candidates.

 

Tip 1: Speak like an investor, not like a planner

 

EY-Parthenon Strategy is the most private-equity-flavored consulting practice outside MBB. Frame your analysis around returns, risk, and value creation. Use language like "investment thesis," "value creation levers," "downside protection," and "payback period."

 

Tip 2: Build financial intuition before you build frameworks

 

EY-Parthenon cases test your gut feel for whether numbers make sense. Memorize the basic math for IRR, payback period, EBITDA margin, and CAGR. If a 5-year forecast projects 30% annual growth, you should immediately know that translates to a 3.7x multiple on year 1 revenue.

 

Tip 3: Drive the case forward without waiting for permission

 

Candidates who wait for the interviewer to tell them what to analyze next lose. Strong candidates state what they want to explore, ask for the data they need, and move to the next step proactively.

 

Tip 4: Practice fast mental math under pressure

 

EY-Parthenon math is rarely complex, but it is fast. You should be able to multiply 480 by 35% in under 15 seconds. Practice with a timer every day in the two weeks before your interview.

 

Tip 5: Always state a hypothesis early

 

Strong candidates state a hypothesis after they walk through their framework, then continuously update it as they learn more. This signals investor-style decision making and saves the interviewer from having to drag the case forward.

 

Tip 6: Quantify everything you can

 

When the interviewer gives you qualitative information, translate it into numbers. "The market is growing fast" becomes "If we assume 15% annual growth, the market doubles every 5 years." Quantification is the single biggest thing that separates strong candidates from mediocre ones.

 

Tip 7: Tie every analysis back to the recommendation

 

After every piece of analysis, say one sentence about what it means for the answer. "Customer retention is 85%, which is above the industry average of 70%, so this strengthens the case for investment." Without this step, the interviewer has to do the synthesis for you.

 

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What Are the Most Common Mistakes Candidates Make?

 

The five most common mistakes in EY-Parthenon Strategy case interviews are using memorized frameworks, ignoring the investor lens, failing to drive the case, weak math execution, and unstructured recommendations.

 

Mistake 1: Using a memorized framework

 

EY-Parthenon interviewers can spot a memorized framework in five seconds. Recycling Porter's Five Forces or the 4Cs without tailoring kills your chances. Build the framework around the specific case prompt every time.

 

Mistake 2: Thinking like a corporate planner, not an investor

 

A planner asks "How do we run this business better?" An investor asks "Should we buy this asset and what return do we get?" If you frame every case as a corporate planning exercise, you will feel off-key for the Strategy practice.

 

Mistake 3: Letting the interviewer drive the case

 

Some candidates pause after each answer and wait for the interviewer to direct the next step. This is the fastest way to fail. State what you want to analyze next, ask for the data, and keep moving.

 

Mistake 4: Math errors and slow math

 

A single wrong number undermines an otherwise strong case. Slow math eats time you need for analysis. Practice with a timer every day in the two weeks leading up to your interview.

 

Mistake 5: A vague or buried recommendation

 

A weak recommendation starts with "Well, it depends" and never lands on a clear answer. A strong recommendation starts with the answer in the first sentence, then justifies it with two or three reasons.

 

Frequently Asked Questions

 

How long is the EY-Parthenon Strategy case interview?

 

Each EY-Parthenon Strategy case interview is 45 to 60 minutes long, with the case portion taking 30 to 45 minutes and the fit portion taking 5 to 10 minutes. Final round Super Days typically include two to four cases across one day. Group case interviews run a separate 60 to 75 minute block.

 

How hard is the EY-Parthenon Strategy case interview compared to MBB?

 

EY-Parthenon Strategy cases are roughly as hard as Bain or BCG cases in structural difficulty, but the math is faster and more finance-flavored. Many candidates report that EY-Parthenon cases feel closer to PE-style due diligence than to traditional MBB strategy cases. The overall offer rate is similar to MBB at around 1% to 3% of applicants.

 

Does EY-Parthenon Strategy hire candidates without MBAs?

 

Yes, EY-Parthenon Strategy hires undergraduates, MBAs, advanced degree candidates, and experienced hires. Undergraduates typically join as Associates, MBAs join as Senior Associates or Consultants, and experienced hires can enter at the Consultant, Manager, or Senior Manager level. Roughly 35% of new hires each year are from non-MBA backgrounds.

 

How long should I prepare for an EY-Parthenon Strategy case interview?

 

Most candidates need 6 to 10 weeks of preparation to reach an interview-ready level for EY-Parthenon Strategy. Plan on 40 to 60 hours of dedicated practice, including 30 to 50 live mock cases. Candidates with no business background often need 10 to 14 weeks.

 

Does EY-Parthenon Strategy ask brainteasers?

 

EY-Parthenon Strategy rarely uses standalone brainteasers, but some interviewers will embed quick estimation or logic puzzles inside a longer case. Examples include estimating revenue per store, payback period on a new product launch, or the number of customers needed to hit a target.

 

What is the EY-Parthenon Strategy offer rate?

 

EY-Parthenon Strategy reports an offer rate of roughly 1% to 3% from application to offer, with final-round conversion of 30% to 40%. This is similar to MBB acceptance rates and significantly more competitive than the broader EY consulting practice.

 

Should I apply to EY-Parthenon Strategy or EY Advisory?

 

Apply to EY-Parthenon Strategy if you want strategy and transactions work similar to MBB. Apply to EY Advisory if you want technology, operations, or implementation work. The two tracks have separate recruiting pipelines, so you typically need to choose one at application.

 

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