PartnerRound- 01Attractive?Size, growth, profit pool
- 02Can we win?Our edge against competitors
- 03How to enter?Build, buy or partner
- 04Does it pay?Payback against the hurdle
By the end you can
- Structure any entry or growth prompt around four decision questions
- Choose between build, buy and partner, and defend the choice with numbers
- Generate growth options that cover every route, not a random list
- Reach a go or no-go with a payback you can calculate on paper
On this page
01The four questions
Market entry and growth cases are decisions: should we do this? So the structure is the set of conditions that must all hold for the answer to be yes. If any one fails, the answer is no, or yes with a condition.
Work in that order where you can: choosing an entry route for an unattractive market wastes time. If the interviewer jumps ahead, follow them, but keep your map so you can say which questions are still open.
02Is it attractive, and can we win?
Attractive means more than big. A $5bn market where ten players fight on price can be worse than a $300m market with healthy margins and room for a newcomer. Look at size, growth, the profit pool (what incumbents earn), how concentrated the market is, and the barriers: licences, regulation, network effects, switching costs.
Size the market top-down, then sanity-check it bottom-up; the market sizing lesson covers both. In an entry case, a defensible number is enough, because precision rarely changes the decision.
Can we win is where most candidates go thin. Name the right to win: a cost advantage, a brand that transfers, a channel the client already owns, a technology, or an existing customer base. Then ask how the leader will respond if you take 5% of its customers.
03Build, buy or partner
Once the market is worth entering, choose the route. Each one trades speed against cost and control.
Regulation can decide it for you. Some countries cap foreign ownership in sectors such as telecoms, media or banking, which can make a joint venture the only way in.
Weak
There are three options: build, buy or partner. Buying is faster but more expensive, building is cheaper but slower, and partnering shares the risk. I'd probably buy.
Strong
I'd lean towards buying, for two reasons. The market is consolidating, so the window to build share organically is closing. And the third-largest player is for sale at about 8 times EBITDA, below the 10 to 12 times recent deals have paid. Building to their size would take us three to four years. Before committing, I'd check integration risk on their IT and whether key customers can walk away on a change of ownership.
Why: The weak answer recites the textbook trade-off and picks without a reason. The strong answer commits, gives reasons specific to this market with numbers, and names what would change its mind.
04Growth cases: finding the options
Growth prompts sound open: the client wants to double revenue in five years. Two moves make them tractable: size the gap, then generate options with a MECE structure rather than a brainstormed list.
Size the gap first. Revenue is $600m today, the target is $1bn in five years, and the core business grows 4% a year on its own. Momentum reaches about $730m, so new initiatives must find the other $270m. That number tells you whether tweaks will do or the client needs something bigger.
Plus new revenue streams: new products or new markets
The matrix comes from Igor Ansoff, who published it in 1957. You do not need to name it in the interview. Use it to check that your ideas cover all four boxes, then prioritise by size of prize, feasibility and risk.
05New product launch
A launch case is market entry with one extra question: how much of the new product's sales come out of products we already sell? That share is cannibalisation, and ignoring it is the most common error in launch maths.
- Need: who has the problem, and what will they pay to solve it?
- Size: target customers × adoption rate × price.
- Cannibalisation: net gain = the new product's contribution - contribution lost on existing products.
- Capability: can we make, sell and support it, or do we need a partner?
- Launch: price point, channel, and whether to pilot in one market first.
- Economics: launch cost, unit margin, breakeven volume and payback.
Use the unit margin after cannibalisation, not before
A snack maker spends $12m to launch a protein bar with a $0.60 unit margin, so breakeven is $12m ÷ $0.60 = 20m bars. But 30% of buyers would otherwise have bought its existing bar, which has a $0.50 margin. The true margin per bar is $0.60 - 0.3 × $0.50 = $0.45, and breakeven rises to about 26.7m bars, a third more.
Check yourself
A new product will sell 10m units at a $0.80 unit margin. 40% of its buyers would otherwise have bought our existing product, which earns $1.00 a unit. What is the net contribution?
06Worked example: go or no-go
Worked example
Should a home-security company install EV chargers?
Prompt. Our client is a home-security company with 1m customers and 800 technicians in a region of 20m households. It is considering installing home chargers for electric vehicles (EVs). The board wants payback within four years. Should it enter?
1. Is the market attractive?
- 20m households × 50% with a driveway or garage = 10m that can fit a charger
- 10m × 2% that get an EV each year = 200,000
- 200,000 × 75% that install a home charger = 150,000 installs a year
- 150,000 × $1,600 per install = $240m a year, growing about 15% a year (the interviewer's figure)
The market is fragmented: local electricians and a few regional installers, the largest with about 8% share. Big enough, growing, no dominant player: attractive.
2. Can we win?
Our edge: a trusted brand already inside 1m homes, technicians who run home visits every day, and a monthly bill we can add a charger plan to. The gap: charger installation needs licensed electricians, so we must hire or train them.
Bottom-up check: our own customers will fit about 7,500 chargers a year (1m × 50% × 2% × 75%). Even if we win half of those, we need about 8% of everyone else's installs to reach a 10% share. Ambitious, but credible.
3. How do we enter?
A regional installer with 8% share is for sale for $30m. On our unit economics it earns about $4m a year (12,000 installs × $500 margin, less $2m of fixed costs), a 7.5-year payback. Even with $2m a year of synergies, payback is 5 years.
Building our own team costs $9m. So build, and partner with a charger maker for hardware prices and car-dealer referrals.
4. Does it pay?
Each install sells for $1,600. The charger costs $700 and labour and travel $400, leaving a $500 margin. Fixed costs (dispatch, marketing, licences) are $2m a year, and we target 10% share by year 3 with no credit for market growth.
Cumulative profit reaches the $9m investment at the end of year 3: a 3-year payback against a 4-year hurdle, before tax and undiscounted, which is how most interviewers want it. Go.
Now find the number the decision hinges on. On the same ramp-up, a 4-year payback needs about 11,300 installs a year by year 3, a 7.6% share. If share stalls at 6%, payback stretches to about 5.4 years and the answer flips to no.
07Tailoring to the client
The four questions hold for every entry case. What sits inside them changes with who is asking and why. Start by asking why the client wants to do this now: a stalled core business, a threat, or an opening only it can exploit.
Check yourself
A private equity fund asks whether to invest in a fast-growing pet insurance company. Which question deserves more weight than it would for a corporate entrant?
Cheat sheet
The lines worth rereading the night before.
- 1Four questions: is the market attractive, can we win, how do we enter, does it pay. Any "no" means no, or yes with a condition.
- 2Attractive means size, growth, profit pool, competition and barriers, not just big.
- 3Can we win means a named advantage competitors cannot copy quickly, and a view on how they will respond.
- 4Build is cheap and slow, buy is fast and expensive, partner shares control. Pick one and give a reason with a number.
- 5Growth: size the gap to the target first, then cover all four Ansoff boxes before you prioritise.
- 6New products: count cannibalisation. Breakeven = fixed cost ÷ unit margin after cannibalisation.
- 7Finish with go or no-go, the payback against the hurdle, and the share or price the decision hinges on.
Now drill it
Reading builds the model; drills make it automatic. Start with the first topic, easiest drills first.
- Market entry7 drills · Decide whether a client should enter a market, and how, with a structure that ends in a go or no-go.
- Growth & new products7 drills · Structure where growth will come from, and judge whether a new product deserves the investment.
- Top-down sizing7 drills · Size a market from the population down, one defensible assumption at a time.
Read the full guide
The same ground on the blog, with more worked examples and practice on the page.
Questions candidates ask
What is the market entry framework for case interviews?
It is four questions: is the market attractive, can we win, how do we enter, and does it pay. Each must come out yes for the recommendation to be yes. Fill each with branches specific to the client rather than a generic checklist.
How do I size a market in a market entry case?
Start top-down from a population you know, narrow it with a few percentages and multiply by price. Then check it bottom-up, for example from the client's own customers or capacity. State every assumption out loud and round to easy numbers: the aim is a defensible order of magnitude, not a precise figure.
When should a company buy rather than build?
Buy when speed matters, a suitable target is available at a fair price, and the capability would take years to build. Build when the client already has most of the capabilities and the market will not close up while it grows. Compare the payback of each route on the same numbers.
What is the difference between a market entry case and a growth case?
A market entry case asks whether to enter one specific market. A growth case asks how to reach a target, so you first size the gap and then generate and rank options, of which entering a new market is only one. Both end in a recommendation with numbers.
How do you calculate payback in a case interview?
Add up profit or cash flow year by year until the cumulative total covers the upfront investment. If it is crossed partway through a year, interpolate: with $10m to recover, $4m earned by the end of year 2 and $8m in year 3, payback is 2 + 6 ÷ 8 = 2.75 years. Interviewers usually accept undiscounted payback unless they ask for NPV.