Private Equity puzzles, solved step by step
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033A business has revenue of 800 and a 12% EBITDA margin. The new owner cuts the cost base by 3% with revenue unchanged. What are the new EBITDA, the new margin and the EBITDA growth?Portfolio operations teamIndian mid-market PE
Try it first
By how much does EBITDA grow?
Show the worked solution
EBITDA rises from 96 to 117.1, a 22% increase, and the margin from 12% to 14.6%. Costs are 800 less 96, which is 704. A 3% cut saves 21.1, and with revenue fixed every rupee of it reaches EBITDA. Because costs are about 7.3 times EBITDA, a small cost change is a large profit change: 3% times 7.33 is 22%.
Why does a 3% cost cut grow EBITDA by 22%?
A family earning Rs 1 lakh a month and spending Rs 88,000 saves Rs 12,000. Trim spending by 3%, about Rs 2,640, and savings jump to about Rs 14,640, up 22%. Profit is the thin slice left after costs, so any change to the large cost base is magnified when measured against the small profit. The magnifier is the ratio of costs to EBITDA, here 704 over 96, about 7.3.
Cutting a cost base of 704 by 3% saves 21.1, which lifts EBITDA from 96 to 117.1 and the margin from 12% to 14.6%, a 22% rise in profit from a small change in costs. How does an operating partner use this, and where does it break?
Multiply by the exit multiple to see what it is worth. At 8x EBITDA, 21.1 of lasting savings adds about 169 of enterprise value, which is why cost programmes sit at the centre of so many buyout plans. The thinner the margin, the bigger the magnifier: at a 5% margin costs are 19 times EBITDA and a 3% cut lifts EBITDA by 57%.
The relationshipc the percentage cut to the cost base Costs / EBITDA how many times larger the cost base is than profit What it says in wordsEBITDA growth from a cost cut equals the cut times the ratio of costs to EBITDA.Say the limitations. Not all of 704 can be cut: raw materials may be fixed by contract and wages by law, so the 3% often has to come from a much smaller part of the base. Cuts that hurt service can cost revenue later. And the same magnifier works in reverse: a 3% cost overrun would take 22% off EBITDA.
Where candidates lose it
The common loss is answering 3%, applying the cut to EBITDA instead of to costs. The interviewer is testing whether you see that costs are many times larger than profit.
The second loss is computing a 15% margin by adding 3 points to 12%. The new margin is 117.1 over 800, which is 14.6%; it rises by 2.6 points, not 3.
What the interviewer asks next
- What revenue growth, with costs growing at the same rate, would deliver the same EBITDA as the 3% cut?
- Which costs in a manufacturing business are hardest to cut, and why?
- If half of the cost base is fixed, what does a 10% revenue fall do to EBITDA?
064Revenue is 1,000 at a 25% EBITDA margin. Depreciation and amortisation are 40, interest is 60, tax is 25%, capex is 50, and working capital is 10% of the revenue growth of 100. Walk from revenue to levered free cash flow.Vista Equity PartnersAustin · 2025
Try it first
What is levered free cash flow?
Show the worked solution
Levered free cash flow is 92.5. EBITDA is 250. Take off D&A of 40 and interest of 60 to get pre-tax profit of 150, tax of 37.5 and net income of 112.5. Add back the 40 of D&A because it is not cash, then subtract capex of 50 and the 10 of working capital the growth absorbs. What remains, 92.5, is cash the owners could take out.
Why does depreciation come off and then go back on?
Think of a delivery van bought last year. Each year the accounts charge a slice of its cost as depreciation, but no money leaves the business that year: the van was paid for already. Depreciation reduces taxable profit, which saves real tax, but it is not a cash payment, so it is subtracted to work out tax and then added back to reach cash. The cash cost of assets enters through capex instead, here 50, which is more than the 40 of depreciation because the business is growing.
EBITDA of 250 loses 60 to interest, 37.5 to tax, 50 to capex and 10 to working capital, leaving levered free cash flow of 92.5; depreciation of 40 appears only inside the tax calculation. Step Amount Revenue 1,000 EBITDA at 25% 250 Less D&A (40) EBIT 210 Less interest (60) Pre-tax profit 150 Less tax at 25% (37.5) Net income 112.5 Add back D&A 40 Less capex (50) Less increase in working capital (10) Levered free cash flow 92.5 Net income of 112.5 plus D&A of 40, less capex of 50 and a working capital increase of 10, gives levered free cash flow of 92.5, the same answer the EBITDA route gives. What makes it levered, and why does a buyout investor want that version?
Levered means after interest: the lenders have been paid. Levered free cash flow is the cash left for the equity holders after the lenders, the taxman and the business's own reinvestment, which is exactly the cash that repays debt in a buyout. Check it a second way from EBITDA: 250 less 60 less 37.5 less 50 less 10 is 92.5. The limit worth saying: working capital is modelled here as 10% of growth, and a real business can swing by far more in a single year.
Where candidates lose it
The most common slip is forgetting to add back depreciation, which gives 52.5 and treats the van as paid for twice, once through depreciation and again through capex.
The second is using the whole working capital balance, 10% of revenue, instead of the increase, 10% of the growth. Only the change in working capital uses cash in the year.
What the interviewer asks next
- What is unlevered free cash flow here, and why is it higher?
- Revenue falls instead of growing. What happens to the working capital line?
- Capitalised software development of 30 sits inside capex. Should a software buyer treat it differently?
Asked at Vista Equity Partners, Private Equity, Austin, 2025 (Wall Street Oasis):
I got a question about getting from revenue to levered free cash flow
090A portfolio company raises its price 5% and loses 5% of its volume. Its contribution margin was 40% of price. Does total contribution rise or fall, and by how much?Mid-market buyout fundPortfolio operations team
Try it first
What happens to total contribution?
Show the worked solution
Contribution rises about 6.9%. On a price of 100 with variable cost of 60, each unit contributes 40. A 5% price rise adds 5 straight to that margin, making 45, a 12.5% rise. Selling 95 units at 45 gives 4,275 against 4,000 before. Volume would have to fall 11.1% before the price rise stopped paying.
Why does a 5% price rise beat a 5% volume loss?
A tea stall sells a cup for Rs 20 that costs Rs 12 to make, keeping Rs 8. Raise the price by Rs 1 and the stall keeps Rs 9: a 5% price rise is a 12.5% rise in what it earns per cup. A price increase falls entirely on the margin because variable cost does not change, so the lower the margin, the bigger the percentage boost. Here the margin is 40% of price, so a 5% price rise lifts contribution per unit by 5 divided by 40, 12.5%.
Before the change 100 units contribute 40 each for 4,000; after a 5% price rise and a 5% volume loss, 95 units contribute 45 each for 4,275, a 6.9% rise, because contribution per unit grew 12.5% while volume fell only 5%. The relationship40, 45 contribution per unit before and after 100, 95 units sold before and after What it says in wordsTotal contribution is units times contribution per unit; volume can fall until the higher margin no longer covers the lost units.What would an operating partner check before raising prices?
The arithmetic says volume could fall 11.1% before this price rise lost money, so the real question is how customers respond. A business whose customers cannot easily switch can usually hold more than 89% of volume after a 5% rise; one in a crowded market with lookalike products may lose far more. Operating teams test price on one region or product line first. Revenue here actually falls 0.25%, which is why a revenue-only dashboard would wrongly call the move a failure.
Where candidates lose it
Candidates say the changes cancel, because plus 5% and minus 5% look symmetric, or they compute revenue, which falls 0.25%, and call it a loss. Neither looks at margin.
Work in contribution per unit. The trap only works on people who forget that variable cost does not rise with price.
What the interviewer asks next
- What if the contribution margin were 80%, as in software? How much volume could you lose?
- With fixed costs of 3,000, what happens to operating profit in percentage terms?
- How would you test customer price sensitivity before a full rollout?
093A portfolio company has fixed costs of 300 and a contribution margin of 40%. The sponsor adds a sales team costing 60 a year. How much new revenue must the team bring in to pay for itself, and how much if the new sales carry only a 35% contribution margin?Portfolio operations team
Try it first
How much new revenue pays for a 60 sales team at a 40% contribution margin?
Show the worked solution
The team needs 150 of new revenue at a 40% margin, and about 171 at 35%. A fixed cost is paid for out of contribution, and each rupee of revenue brings only 40 paise of it: 60 divided by 0.40 is 150. If the team wins sales by discounting and the margin falls to 35%, the hurdle rises to 60 divided by 0.35, about 171. Breakeven revenue moves from 750 to 900.
Why is the answer not simply 60?
A shop hires a helper for Rs 6,000 a month. If every Rs 100 of sales costs Rs 60 in stock, the helper must bring in Rs 15,000 of extra sales, not Rs 6,000, because only Rs 40 of each Rs 100 is left to pay wages. New fixed costs are paid out of contribution, so the revenue needed is the cost divided by the contribution margin. At 40%, 60 of cost needs 150 of revenue.
Contribution at 40% of revenue covers fixed costs of 300 at revenue of 750; adding 60 of fixed cost moves breakeven to 900, so the sales team must bring in 150 of revenue, or about 171 if its sales carry a 35% margin. The relationshipDelta F the new fixed cost, 60 m contribution margin on the new sales Delta R new revenue needed to break even on the hire What it says in wordsDivide the new fixed cost by the margin the new sales earn.What would an operating partner ask before approving the hire?
Breakeven is the floor, not the case for the hire: the team should bring in well above 150 within a reasonable ramp, at a margin close to the existing 40%. Sales teams often win volume with discounts, which is exactly what drops the margin to 35% and lifts the hurdle to 171. The partner would also ask how long the ramp takes, because a team that needs a year to sell anything costs 60 before it earns a rupee.
Where candidates lose it
The fast wrong answer is 60: matching the cost with the same amount of revenue, as if revenue were profit. Variable costs take 60% of every rupee before anything is left to pay the team.
The second miss is assuming new sales carry the existing margin. A sales team that buys growth with discounts can raise revenue and still fail to pay for itself.
What the interviewer asks next
- How many months of ramp can the sponsor afford if the team reaches 300 of annual sales by year end?
- The team's sales carry a 50% margin because they sell a premium line. What is the hurdle now?
- How does a commission-only sales structure change this calculation?
