EY-Parthenon Case Interview: Strategy Consulting at a Big Four Firm

EY-Parthenon is the strategy consulting arm of EY, one of the Big Four accounting firms. Unlike EY’s broader Advisory Services group (which focuses on implementation and technology), EY-Parthenon operates as a pure strategy practice — doing the same type of work you’d find at McKinsey, BCG, or Bain: corporate strategy, due diligence, commercial assessments, and transformation. Based on our analysis of over 200 candidate interviews, EY-Parthenon’s case interview difficulty sits between MBB and general Big Four consulting, with a distinctive emphasis on private equity due diligence and sector-specific strategy.

EY’s Two Consulting Arms: Know the Difference

Before diving into interview prep, understand which part of EY you’re targeting. The interview process and case style differ substantially between the two consulting practices.

EY-Parthenon candidates face rigorous case interviews similar to what you’d experience at MBB. If you’re interviewing for Advisory Services instead, expect more emphasis on behavioral questions and less intensive case work. This guide focuses specifically on EY-Parthenon — if you’re targeting Advisory, your preparation should weight behavioral prep more heavily.

EY-Parthenon Interview Process

The EY-Parthenon recruiting process has more stages than typical Big Four interviews, incorporating digital assessments before you reach human interviewers. Based on our tracking of 200+ candidates, roughly 60% of applicants are screened out before the first live interview—primarily in the online assessment and video interview stages.

Here’s the complete interview flow:

flowchart LR
    A[Application] --> B[Online Assessment]
    B --> C[Video Interview]
    C --> D{Pass?}
    D -->|Yes| E[First Round Cases]
    D -->|No| F[Rejected]
    E --> G[Final Round]
    G --> H[Offer]

The Online Assessment

EY’s online assessment tests three areas: numerical reasoning (data interpretation, basic calculations), verbal reasoning (reading comprehension, logical deduction), and situational judgment (workplace scenarios). Based on candidate feedback, the numerical section is the most challenging — practice interpreting charts and tables under time pressure. You typically have 60-90 seconds per question.

The Video Interview

EY’s video interview consists of 5 behavioral questions. You get 60 seconds to prepare and 90 seconds to record your answer for each question. You can re-record once per question if needed. Some EY offices use AI to evaluate initial responses, focusing on communication clarity and content structure. Treat this as a real interview — dress professionally, use good lighting, and structure your responses with the STAR method.

EY-Parthenon Case Interview Format

EY-Parthenon cases are interviewer-led, similar to McKinsey’s format. The interviewer presents a business problem in stages, asks specific questions, and provides data exhibits as you progress. Cases typically run 25-30 minutes, with 10-15 minutes for behavioral discussion in the same interview slot.

Key characteristics of EY-Parthenon cases:

• Private equity focus — roughly 30% of cases involve PE due diligence, investment thesis, or portfolio company strategy
• Sector specialization — EY-Parthenon has strong healthcare, education, and financial services practices; expect industry-specific cases if you’re targeting these sectors
• Commercial due diligence — “Should our client acquire this company?” is a common case stem
• Hypothesis-driven — interviewers expect you to form and test hypotheses, not just explore open-endedly

Case Type Distribution

The heavy M&A weighting reflects EY-Parthenon’s strong private equity practice. If you’re joining the Transaction Strategy team specifically, expect M&A cases in 50%+ of your interviews.

How EY-Parthenon Differs from MBB

EY-Parthenon cases share the interviewer-led format with McKinsey but differ in several ways:

EY-Parthenon’s interview process is more structured and multi-stage than MBB, but the case interviews themselves are slightly less intense. In our experience, candidates who struggle with BCG’s open-ended brainstorming often perform better in EY-Parthenon’s more guided format.

Preparation Strategy

For Cases

Your case prep should emphasize three areas that EY-Parthenon weights heavily:

1. M&A and due diligence fundamentals — Understand investment thesis structure, revenue and cost synergies, integration risks, and how PE firms evaluate targets. Practice with our M&A case framework guide.

2. Sector knowledge — If you’re targeting a specific industry practice (healthcare, education, financial services), develop genuine expertise. EY-Parthenon interviewers expect you to bring relevant insights, not just generic frameworks.

3. Hypothesis-driven problem solving — Practice forming a hypothesis within the first 2 minutes of a case and explicitly testing it. Interviewers reward candidates who say “My hypothesis is X, and I’d test it by examining Y” over those who broadly explore.

For Behavioral Interviews

EY-Parthenon behavioral questions focus on teamwork, client management, and “why EY-Parthenon specifically.” Prepare stories covering:

• A time you collaborated with a difficult team member
• How you handled ambiguity or incomplete information
• Why strategy consulting over other career paths
• Why EY-Parthenon over MBB or other Big Four

The “why EY-Parthenon” question appears in nearly every interview. Generic answers about “great people” or “interesting work” fall flat. Research EY-Parthenon’s specific practice areas, recent deals, and how the PE focus differentiates it from MBB. Mention specific EY-Parthenon engagements or sector expertise that aligns with your interests.

For the Online Assessment

Practice numerical reasoning with timed exercises — you need speed and accuracy under pressure. Focus on:

• Interpreting bar charts, line graphs, and tables quickly
• Calculating percentages, growth rates, and ratios mentally
• Drawing conclusions from multiple data sources

Our mental math guide covers the calculation techniques you’ll need.

Preparation Timeline

Use the AI Mock Interview for unlimited case practice — it’s particularly useful for drilling M&A case structures and getting feedback on hypothesis formation.

Frequently Asked Questions

What is EY-Parthenon?

EY-Parthenon is EY’s strategy consulting division, formed in 2014 when EY acquired the Parthenon Group. It focuses on corporate strategy, M&A due diligence, and private equity consulting—doing the same type of work you’d find at McKinsey, BCG, or Bain.

How many rounds are in the EY-Parthenon interview?

The full EY-Parthenon interview process includes: application screening, online assessment (45-60 min), video interview (5 behavioral questions), first-round case interviews (1-2 interviews), and final round (2-3 partner interviews). Roughly 60% of candidates are screened out before the first live interview.

How does EY-Parthenon differ from MBB interviews?

Both use interviewer-led cases (similar to McKinsey), but EY-Parthenon has a higher proportion of PE due diligence cases (~30% vs MBB’s 10-15%), more interview stages (including online assessment and video interview), and overall case difficulty sits between MBB and general Big Four.

What’s the difference between EY-Parthenon and EY Advisory?

EY-Parthenon focuses on strategy consulting (corporate strategy, PE due diligence) with rigorous case interviews. EY Advisory Services focuses on technology implementation, risk management, and performance optimization, with more behavioral-heavy interviews and lighter case work. Confirm which division you’re targeting before applying.

Key Takeaways

• EY-Parthenon is EY’s strategy consulting arm, doing MBB-equivalent work — don’t confuse it with EY Advisory Services (which focuses on implementation)
• The interview process includes online assessment + video interview before live case interviews — roughly 60% of candidates are filtered before the first human interview
• Cases are interviewer-led (like McKinsey) with heavy emphasis on M&A and PE due diligence (~30% of cases)
• EY-Parthenon has strong sector practices in healthcare, education, and financial services — expect industry-specific cases if targeting these areas
• Prepare a compelling answer for “why EY-Parthenon over MBB” — interviewers expect you to understand the PE focus and sector specialization that differentiates the firm
• The case difficulty sits between MBB and general Big Four — rigorous but slightly more structured than BCG or Bain

Ready to start? Browse EY cases in our case library, master the M&A framework for EY-Parthenon’s most common case type, or get unlimited practice with the AI Mock Interview.