L.E.K. case interview: 4 practice cases with worked examples (2026)

The L.E.K. case interview is a live business problem, usually candidate-led: you clarify the question, build the structure, ask for data and drive to a recommendation. It is commonly described as heavy on market sizing, which often opens a case or comes as a standalone estimate, and its cases lean towards the firm's core work: due diligence for private equity investors, life sciences and healthcare, and profitability and growth problems across sectors. Most processes run two rounds of case interviews with questions about your background, and some offices are commonly reported to use a written or numerical case test. Formats vary by region and level, so check your invitation.

L.E.K. Consulting was founded in London in 1983 by three former Bain partners, James Lawrence, Iain Evans and Richard Koch, whose initials give the firm its name. It is a strategy firm, usually grouped with the tier 2 firms just below MBB, and it is particularly well known for private equity due diligence and for life sciences work. If you are also applying to Big 4 strategy arms, our EY-Parthenon guide covers the closest peer.

Our library has two cases written in L.E.K.'s style, both candidate-led. We add two from other firms' styles that match L.E.K.'s themes: a healthcare pricing case written in BCG's style and a private equity due diligence written in EY-Parthenon's style. Each has a guided walkthrough.

New to cases? Start with Silverpine: one clean profit bridge, no specialist vocabulary. Halden and Ridgeline are the hardest and the closest to L.E.K.'s sector work.

The method is the same: clarify, structure, analyse, recommend. What changes is the weight on estimation and on sector context, both of which come from the firm's work.

So make estimation automatic, and get comfortable with sector vocabulary: patients, payers and prescribers in healthcare; markets, share and returns in due diligence. You do not need specialist knowledge, but you do need to reason quickly when the case uses it. The market sizing lesson is the right place to start.

For each case: the prompt, a structure that fits, the first exhibit and its first calculations, then the hypothesis you would say out loud. The rest is left for you to play.

Silverpine Resorts: a ski operator's profit slide (profitability, leisure)

The prompt. Silverpine Resorts operates three ski resorts in New England. EBITDA has fallen from $50m to $28m over three seasons, and the CEO puts it down to three poor winters. The board is not convinced and wants to know what is really driving the decline and what to do about it.

A structure that fits. Split EBITDA into revenue and costs. Split revenue by how customers pay: day tickets (visits × price), season passes (holders × price) and ancillary spend (visits × spend per visit). Separate weather, which shows up in operating days, from Silverpine's own decisions on pricing. Split labour into hours × cost per hour and ask whether hours flex with the snow. Then build a bridge and rank the drivers by size and controllability.

In the case this is a line chart. One fact sits beside it: Silverpine relaunched its season pass at a lower price for 2023/24. The first calculations. Revenue fell $141.6m - $129.8m = $11.8m (8%), and costs rose $101.6m - $91.6m = $10.0m (11%). Together that is the $21.8m fall, and costs explain about 46% of it. Now the shape: revenue fell $3.6m, $3.5m and $4.7m in successive seasons, and costs rose every season. That is a steady decline, not a dip and a recovery.

L.E.K.Silverpine Resorts' profit slidesProfitability · Medium

Silverpine Resorts' profit slides

Cost the pass relaunch customer group by customer group, test the labour model and build the full bridge.

Interviewer

Our client, Silverpine Resorts, operates three ski resorts in New England. EBITDA has fallen from $50m to $28m over the last three seasons, and the CEO puts it down to three poor winters. The board is not convinced and wants to know what is really driving the decline and what to do about it. How would you approach this?

Start the caseGuided, step by step

Halden Pharma: forecasting a diabetes launch (new product, life sciences)

The prompt. Halden Pharma, a mid-size pharmaceutical company, has a once-weekly injectable for type 2 diabetes, HLD-217, that has just completed phase 3. It launches in the US in 2027, into a class led by much larger competitors. The CEO wants to know how big the drug can be and what price to launch at.

A structure that fits. Write the revenue equation first and hang every question off one of its terms. The patients come from a funnel. Share depends on formulary access, differentiation and the competition's response. Paid months depend on how long patients stay on therapy. Net price depends on what payers pay for the incumbents. Then test Halden's ability to reach the doctors who prescribe.

The first calculations. Run the funnel out loud and keep every stage: 35m × 80% = 28m diagnosed; × 75% = 21m treated; × 40% = 8.4m eligible; × 60% = 5.04m on a GLP-1 at peak. That is about 14% of everyone with the disease. Applying a share to the 35m would overstate the pool about seven times (35 ÷ 5.04 ≈ 6.9).

L.E.K.Halden Pharma launches a weekly diabetes injectableNew Product · Hard

Halden Pharma launches a weekly diabetes injectable

Compare price scenarios, read the persistence curves with care and decide how a mid-size company reaches primary care.

Interviewer

Our client, Halden Pharma, is a mid-size pharmaceutical company. Its once-weekly injectable for type 2 diabetes, HLD-217, has just completed phase 3 and will launch in the US in 2027, into a class led by much larger competitors. The CEO wants to know how big the drug can be and what price to launch at. How would you approach it?

Start the caseGuided, step by step

Both are written in other firms' styles, but each matches a theme L.E.K. is known for: pricing a healthcare product from the value it creates, and diligence for a private equity fund.

Helix Diagnostics: pricing a faster infection test (pricing, healthcare; written in BCG's style)

The prompt. Helix Diagnostics has developed a blood test that detects a particular post-surgical infection 40 hours earlier than the current standard of care. It is about to launch in US hospitals and needs to set a price. What should it charge?

A structure that fits. Bracket the answer before choosing it. The floor is Helix's cost per test. The reference is the test hospitals buy today. The ceiling is the value of earlier detection to the hospital, spread across every patient tested. Then decide what share of that value to capture, and whether price should vary by type of hospital.

Both tests are run on every patient after a target procedure, and hospitals are paid a fixed amount per procedure, so complications come out of their own margin. The first calculations. A typical hospital sees 1,200 × 6% = 72 infections a year. It spends 1,200 × $45 = $54,000 a year on the current test. Running the same volume costs Helix 1,200 × $62 = $74,400, so a price anywhere near the current test loses money on every test.

BCGHelix Diagnostics prices a new testPricing · Hard

Helix Diagnostics prices a new test

Find the value per test without falling into the denominator trap, then choose a price and a segment to lead with.

Interviewer

Helix Diagnostics has developed a blood test that detects a particular post-surgical infection 40 hours earlier than the current standard of care. They are about to launch in US hospitals and need to set a price. What should they charge?

Start the caseGuided, step by step

Ridgeline Capital: diligence on a vet roll-up (private equity, healthcare services; written in EY-Parthenon's style)

The prompt. Ridgeline Capital, a mid-market private equity fund, is bidding for Larkspur Veterinary Partners, which runs 145 vet clinics in the US Southeast. Larkspur's revenue has grown about 22% a year for three years, and the seller wants $960m, 16 times last year's EBITDA. Ridgeline has four weeks until final bids and wants commercial due diligence.

A structure that fits. Separate the market from the company's two engines. The market: size, fragmentation and growth as pets × visits per pet × spend per visit. The organic engine: same-clinic growth in visits and price, and the vets to deliver it. The acquisition engine: clinics left to buy and what they cost. Then rebuild the plan and test the price against the fund's return hurdle.

The market was about $11bn in 2025. The first calculations. Start with volume: from 2022 to 2025, the number of visits grew about 1.5% - 1.0% = 0.5% a year, so spend per visit delivered 7 of the 7.5 points of growth. Forward, the drivers add to 1.0% - 0.5% + 5.5% = about 6% a year, which takes the market from $11bn to about $13.1bn by 2028 (11 × 1.06 × 1.06 × 1.06).

EY-ParthenonRidgeline Capital bids for a vet clinic roll-upM&A · Hard

Ridgeline Capital bids for a vet clinic roll-up

Separate earned growth from bought growth, find the real constraint in the clinics and set a price the fund can defend.

Interviewer

Our client, Ridgeline Capital, is a mid-market private equity fund bidding for Larkspur Veterinary Partners, a group of 145 vet clinics in the US Southeast. Larkspur's revenue has grown about 22% a year for three years, and the seller is asking $960m, 16 times last year's EBITDA. Ridgeline has four weeks until final bids and has asked us for commercial due diligence. How would you approach it?

Start the caseGuided, step by step

Because sizing comes up so often at L.E.K., have one routine you trust and run it the same way every time, whether the question is a standalone estimate or the first step of a due diligence.

Life sciences cases. Candidates applying to life sciences teams may meet cases about drug launches, diagnostics or medical devices. You do not need clinical knowledge; the interviewer will give you the facts. What helps is knowing how the vocabulary turns into maths.

Written and numerical tests. Some L.E.K. offices are commonly reported to use a written or numerical case test, for example an online numerical test early in the process, or a case worked from a data pack on paper and then discussed. Formats differ by office, level and year, so ask the recruiter what each round contains, and practise maths on paper as well as out loud.

• You can size a market from a cold start in five to seven minutes, with a sanity check at the end.
• You run a funnel stage by stage and say each intermediate number out loud.
• You split any profit change into revenue and cost, then into drivers, and say which are within the client's control.
• You price from value, using cost as the floor and the competitor as a reference.
• In a due diligence case you separate the market, the target's position, the plan and the price.
• You close with one number and a recommendation in under a minute.
• You have a clear answer to 'why L.E.K.?' that goes beyond its sectors, and six to eight stories about your background.

Play each case twice. First live: talk out loud, drive the structure yourself and time it at 30 to 40 minutes. Then open the guided walkthrough and compare your answers step by step. Wherever you lost time or a number, spend the next day on the matching drill. Our market sizing questions guide and case interview math guide are the best companion reads for L.E.K.