Marsh McLennan runs four visibly different loops under one roof. Oliver Wyman, the strategy-consulting arm, is a classic case-interview firm: an online quantitative/situational assessment, then two rounds mixing fit interviews with two to four cases, often with a financial-services or insurance flavour and noticeably heavy mental math. Mercer, Marsh and Guy Carpenter run a much lighter, behaviour-led process: a one-way HireVue recording, then a 'super day' or panel of three to four short 1-on-1 conversations with brokers, consultants or managers, with STAR answers and a well-researched 'why Marsh / why Mercer' doing most of the work. UK and European graduate hiring adds an assessment-centre layer with a group exercise and a short presentation.
These 41 writeups cover management consulting, actuarial, insurance broking and other roles, US-heavy, UK/EU strong second. All of them were posted under a pseudonym (Reddit, GeeksforGeeks or forum handles), so we could not verify the authors’ identities.
Typical rounds
21-3 range
Outcomes shared
25/11offer / not
Most common round
Phone screen
Sources span
2011 - 2026
Most frequently reported · Behavioral(35), Case study(17), Aptitude(12), Domain knowledge(11), Resume deep-dive(7)
Marsh McLennan’s official process
Oliver Wyman publishes its own interview-preparation page describing a mix of conversational interviews (background, motivation, career goals) and case interviews. It frames the case as an assessment of how a candidate breaks an unstructured problem into components, asks for data, states assumptions, uses numbers carefully and lands on a practical recommendation, and it links a set of sample cases (grocery, pharmacy, dairy, oil and gas pricing, water park) that mirror real client work. Marsh McLennan's own careers site has no equivalent public process page that resolved.
Campus-recruiting first round of two case interviews with junior consultants; moderate difficulty with some arithmetic and no market-sizing or trick questions.
Covered · Case study, Behavioral
2
Two cases with principals or partnersFinal
A second pair of cases with principals or partners, plus conventional fit questions on motivation, interests outside work and a couple of projects explained concisely.
An Oliver Wyman-specific maths test taken after the CV and cover letter; deliberately long so that finishing every question is not expected, and it cuts the field to roughly thirty per campus.
Covered · Aptitude
2
Two short case interviewsCase study
Two roughly 20-minute interviews with analyst- to associate-level consultants, spent entirely on cases with essentially no small talk.
Covered · Case study
3
Final dayFinal
Four 45-minute interviews, three cases and one resume-based, with interviewers from associate consultant up to partner. Candidates were flown in the night before for dinner with the team and heard the outcome the same day.
Two interviews split roughly evenly between fit and casing.
Covered · Case study, Behavioral
2
Three interviewsFinal
Three more interviews with the same fit-and-case mix; case difficulty ranged from very easy to genuinely hard, and interviewers came across as relaxed and conversational.
A standard on-campus pipeline with two rounds of cases; the candidate was cut and noted the cases leaned on logic puzzles and more real business knowledge than expected.
The candidate described the FS interviews as unlike a conventional case: loosely structured conversations about quantitative topics rather than a scripted case format, which they felt could not really be crammed for.
After the application (and a RARE contextual-recruitment questionnaire), an online assessment combining competency and behavioural questions with an untimed but time-tracked numerical section, returning a strengths-and-weaknesses report to the candidate.
A recorded HireVue for the Mercer graduate analyst route, sent by Marsh & McLennan's UK recruitment team, in which the candidate was asked to talk about what they knew about Marsh & McLennan rather than only about Mercer.
A recorded interview within a day or two of applying, opening with a question asking the candidate to explain in their own words what the firm does, then several behavioural and situational prompts.
Covered · Behavioral, Domain knowledge
2
Virtual interview eventPanel
A group Zoom session that split candidates into four consecutive 30-minute breakout rooms, each with a single interviewer asking behavioural questions in a deliberately conversational style. Decision came about a week later.
A personality-led call from an HR representative about handling setbacks and tight deadlines.
Covered · Behavioral, STAR stories
2
Two-interviewer ZoomPanel
A video interview with one actuarial and one investments employee covering coursework and projects; the candidate described it as only as technical as they chose to make it, plus questions on interest in Mercer's wealth business.
A 15-minute group discussion on a set question, then solo preparation and delivery of a short presentation to an assessor drawing on that discussion, informal time with current analysts, and finally a one-on-one behavioural interview with a manager covering things like delegating.
Senior health and benefits consulting analyst (Mercer)
Experienced
Received an offer2 rounds
1
Recruiter phone screenPhone screen
A recruiter screen a week or two after a cold online application.
Covered · Resume deep-dive
2
Three team interviewsPanel
Three separate Zoom interviews with different team members mixing light technical and behavioural questions, with no case study, estimation or written test.
A recorded interview of roughly three to five questions after the online application, focused on why Marsh, why risk management, and some STAR-style prompts.
Covered · Behavioral, STAR stories
2
Super dayPanel
Two to four weeks later, three 30-minute conversations with brokers ranging from recent TRAC graduates to senior brokers with decades of experience, covering background, why Marsh, what Marsh actually does, and previous internships.
A simple behavioural on-campus interview run alongside many other students; the candidate felt selection hinged largely on personality fit and was cut here. Those who passed went to a Marsh super day at the office with several managers.
A recorded interview issued within days of applying.
Covered · Behavioral
2
Three 30-minute interviewsPanel
About a month later, three 30-minute behavioural interviews including a why-Marsh question, with interviewers sometimes asking for more than one example per question. The offer arrived a week after the final round.
Two to three weeks after the CV submission, a short form covering graduation date, full-time availability during the programme, business-level languages, and a choice of two preferred teams from consulting, cyber security, operations, actuarial/pensions analytics, investments analytics and finance.
Covered · Shift availability, Language skills
2
Recorded online interviewPhone screen
A roughly 30-minute recorded interview of four questions: self-introduction, what the candidate knows about Marsh, why they would add value, and what they expect to learn.
Covered · Behavioral, Domain knowledge
3
Manager interviewHiring manager
A scheduled interview with the hiring manager; the candidate was still waiting on this stage when they wrote up the process.
A single one-hour final round split into a 45-minute case study with two analysts and a 15-minute behavioural segment with HR. The candidate was invited straight to the final round and heard back by phone within three business days, with over two weeks to decide.
Full loop: screen, interviews, presentation and testsAssessment centre
A short, transparent process combining a phone screen, one-on-one interviews, a presentation, a skills test and a personality assessment; the candidate praised the clarity of communication throughout.
What is the interview process like at Marsh McLennan?
Marsh McLennan runs four visibly different loops under one roof. Oliver Wyman, the strategy-consulting arm, is a classic case-interview firm: an online quantitative/situational assessment, then two rounds mixing fit interviews with two to four cases, often with a financial-services or insurance flavour and noticeably heavy mental math. Mercer, Marsh and Guy Carpenter run a much lighter, behaviour-led process: a one-way HireVue recording, then a 'super day' or panel of three to four short 1-on-1 conversations with brokers, consultants or managers, with STAR answers and a well-researched 'why Marsh / why Mercer' doing most of the work. UK and European graduate hiring adds an assessment-centre layer with a group exercise and a short presentation.
What topics does Marsh McLennan test in interviews?
Commonly reported topics include Case study, Market sizing, Behavioral, STAR stories, Aptitude, Resume deep-dive.
These guides summarize public, first-hand interview experiences shared by candidates. They describe the shape of each loop and the topics that came up, not a leaked question bank, and every experience links back to its original source. Processes change often; treat this as directional prep, not a script.