Hedge Funds puzzles, solved step by step
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012A fund's NAV falls from 100 to 80 in year one and rises to 110 in year two. It charges a 20% performance fee above a high-water mark tracked separately for each investor. Investor A came in at 100 at the start of year one; investor B came in at 80 at the start of year two. On how much gain does each pay the fee in year two?Fund of funds and allocatorsMulti-manager platforms
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In year two, on how much gain per unit does investor A pay the fee?
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Investor A pays the fee on 10 per unit, a fee of 2; investor B pays it on 30, a fee of 6. Each high-water mark is the highest value that investor's own units have reached: 100 for A, who lived through the fall, and 80 for B, who bought at the bottom. The fund made 37.5% in year two for both of them, yet B pays three times A's fee, because every point B made is new profit for B.
Why does the same year produce two different fees?
Two shopkeepers pay a helper a bonus only when monthly sales beat their own best month so far. One had a record month last year and a slump since; the other opened last month. The same good month earns the helper a bonus from the new shop and little or nothing from the old one. A high-water mark is personal: it is the peak value of that investor's own units, so it depends on when they came in. A bought at 100 and watched it fall to 80, so the rise back to 100 only repairs A's loss. B bought at 80, so the whole rise to 110 is new money for B.
The fund falls from 100 to 80 and rises to 110; investor A's high-water mark of 100 means A is charged only on the 10 above it, a fee of 2, while investor B's mark of 80 means B is charged on the full 30, a fee of 6. Investor Entry NAV High-water mark NAV, end of year 2 Gain charged Fee at 20% NAV after fee A 100 100 110 10 2.0 108.0 B 80 80 110 30 6.0 104.0 Per unit, investor A is charged on 10 and keeps 108, while investor B is charged on 30 and keeps 104, although both held the same fund through the same year. How do funds keep the two investors apart?
If the fund kept one NAV and one mark for everyone, either A would be charged on a recovery or B would ride free on 20 points of profit. Funds solve this with per-investor accounting: a separate series of units for each subscription date, or equalisation adjustments, so each investor pays on their own gain and nobody else's. Series are the easier version to explain in the room: B's units are a new series that starts life with a mark of 80. The limitation is worth a line: not every fund does this, so an allocator reads the offering document before assuming it.
What does this do to the manager's incentives?
A manager whose older investors sit below their marks earns no performance fee on them until the loss is repaid. For an allocator, a high-water mark is a fee holiday on the recovery, and it belongs only to the investors who stayed through the loss. For a manager deep under water it can mean years of work for no incentive fee, which is why some funds in that position close and relaunch rather than climb back to their marks, and why allocators ask about it.
Where candidates lose it
Candidates work out one fee for the whole fund, usually 20% of the year's 30 point gain, and apply it to everyone. That overcharges A by 4 per unit, which is precisely what per-investor marks exist to prevent.
The mirror mistake is giving B the benefit of A's mark and charging only the gain above 100. B never lost anything; every point from 80 to 110 is B's profit. The fee follows the investor, not the fund.
What the interviewer asks next
- If the NAV had only reached 95 in year two, what would each investor pay?
- How would a 5% hurdle rate change A's and B's fees?
- Why might a manager well below the high-water mark close the fund and launch a new one?
047An index rises 10% one day and falls 10% the next. What happens to the index over the two days, and to a fund that delivers exactly twice the index's daily return?Fund of funds and allocatorsMulti-manager platforms
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Over the two days, the 2x fund is
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The index ends down 1% and the 2x fund down 4%, not 2%. The index goes 100, 110, 99. The fund goes 100, 120, 96, because it doubles each day's move: up 20%, then down 20% of a bigger number. Two days of index returns of plus and minus r cost the index r squared, 1%, but cost the 2x fund 4r squared, 4%. The drag comes from resetting leverage daily, and it grows with volatility.
Why is the index down at all after up 10% and down 10%?
A salary cut of 10% after a 10% raise leaves you below where you started, because the cut is taken on the bigger salary. An up move of r followed by a down move of r multiplies to (1 + r)(1 - r) = 1 - r squared, so the index loses r squared, here 1%. This is the same volatility drag that makes compound returns lower than average returns. It is small for the index because r squared is small.
Why does the 2x fund lose four times as much?
Because it resets its leverage each day. The fund multiplies to (1 + 2r)(1 - 2r) = 1 - 4r squared, so its drag is four times the index's, not two times. With r = 10% that is 4%. A buyer expecting twice the index return over the period expected 2 x (-1%) = -2% and got -4%. The extra 2 points is the price of re-levering after the gain, which buys more exposure at the top, and de-levering after the loss.
Over two days of plus and minus 10%, the index ends at 99, down 1%, while the fund that doubles each daily move ends at 96, down 4%, twice the naive 2% loss, because leverage is reset every day. The relationshipL the daily leverage multiple, 2 r the size of each day's index move, 10% What it says in wordsA leveraged fund's drag in a choppy market grows with the square of the leverage.Say where the drag does not apply. In a steady trend, daily resetting helps: two days of +10% take the index to 121 and the 2x fund to 144, more than the naive 142. Daily-reset leveraged funds win in trends and lose in chop, so holding one for months is a bet on the path, not just the direction. That is why allocators treat them as trading tools rather than long-term holdings.
Where candidates lose it
The common loss is saying the 2x fund is down 2%, doubling the index's two-day result. The fund doubles each daily return, and the compounding does the rest.
The second loss is saying the index is flat. Up 10% and down 10% is always a loss; say 1 minus r squared and the two answers come together.
What the interviewer asks next
- What is the two-day return of a fund delivering minus twice the daily return?
- Over a year with 20% index volatility and no trend, roughly how much does a 2x daily fund lag twice the index return?
- Two days of +10%: how does the 2x fund compare with twice the index return?
072An investment earns 10% a year before fees and charges a 2% annual fee. Over 20 years, what share of the investor's ending wealth does the fee consume?Fund of funds and allocatorsMulti-manager platforms
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Over 20 years, what share of the ending wealth does the 2% fee take?
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About 31% of the ending wealth. Rs 1 lakh growing at 10% a year becomes Rs 6.73 lakh in 20 years; at 8% after the fee it becomes Rs 4.66 lakh. The fee takes Rs 2.07 lakh, about 31% of what the investor would otherwise have had, although each year it looks like only a fifth of the return.
Why does a fifth of each year's return become almost a third of the wealth?
Think of a mango tree whose fruit you replant. If a neighbour takes one mango in every five each year, you lose those mangoes and every tree they would have grown. A fee taken every year removes money that would itself have compounded for the remaining years, so its cost grows faster than the fee rate suggests. The share lost is 1 minus (1.08/1.10) to the 20th: each year the investor keeps 98.2% of what the gross path would have held, and 0.982 to the 20th is about 0.69.
The relationship1.10 the gross growth factor each year 1.08 the growth factor after the 2% fee 20 the number of years What it says in wordsThe fraction of wealth the fee takes is one minus the ratio of the two growth paths after 20 years.Rs 1 lakh grows to Rs 6.73 lakh in 20 years at 10% but only Rs 4.66 lakh at 8% after the fee, a gap of Rs 2.07 lakh that widens every year and ends at about 31% of the gross wealth. How do you estimate it without a calculator?
Use the rule of 72. At 10% money doubles about every 7.2 years, so 20 years is about 2.8 doublings, near 7 times; at 8% it doubles every 9 years, about 2.2 doublings, near 4.6 times. The exact numbers are 6.73 and 4.66, so the estimate lands within a few per cent, and 4.6 over 6.9 already tells you roughly a third is gone. Say the estimate first, then the exact figure.
What does an allocator take from this?
That fees should be judged against the return they leave, over the holding period, not as a percentage in a single year. A manager charging 2% needs to beat a cheaper alternative by about 2 points a year, every year, just to leave the investor level; over 20 years the difference is 31% of the pot. Hedge fund fees often add a share of profits on top, which widens the gap further. The illustration assumes a steady 10%; real returns vary, but the compounding of the fee does not depend on that.
Where candidates lose it
The two fast answers are 2% and 20%: the fee rate, or the fee as a share of one year's return. Both treat the fee as a one-year cost and ignore that every rupee taken would have compounded for the years that follow.
The second loss is working out 4.66 and 6.73 and then reporting the gap as a share of the smaller number, 44%. The question asks what share of the investor's potential wealth the fee consumed, so divide by the gross figure.
What the interviewer asks next
- The fee is 1% instead of 2%. What share of ending wealth does it take over 20 years?
- Add a 20% share of profits on top of the 2% fee. Roughly what does the investor keep?
- Why do fees matter more for a 30-year retirement saver than for a 3-year investor?
087A fund charges 2 and 20 and earns a gross return of 12% on Rs 1,000 crore. Investors push the management fee down to 1%. What performance fee keeps the manager's total fee income unchanged at that return?Two SigmaNew York · 2026
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What performance fee keeps the manager whole?
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About 27.3%. At 2 and 20 the manager earns Rs 20 crore of management fee and 20% of the remaining Rs 100 crore gain, Rs 20 crore: Rs 40 crore in all. At 1%, the management fee is Rs 10 crore and the gain after it is Rs 110 crore. To keep Rs 40 crore the performance fee must bring in Rs 30 crore, which is 30/110, or 27.3%. The two deals match only at a 12% gross return.
What does the manager earn today?
Think of a tailor who charges a fixed stitching fee plus a share of whatever the finished suit sells for above cost. Cut the fixed fee and the share must rise to keep the same income, but the share now applies to a slightly larger base. At 2 and 20 on Rs 1,000 crore earning 12%, the manager takes Rs 20 crore of management fee plus 20% of the Rs 100 crore gain left after it, Rs 40 crore in total. Investors keep Rs 80 crore, a net return of 8%.
Under 2 and 20 the manager's Rs 40 crore is Rs 20 crore fixed plus 20% of Rs 100 crore; under a 1% fixed fee it is Rs 10 crore plus 27.3% of Rs 110 crore, because the smaller fixed fee leaves a larger gain for the performance fee. How do you find the new performance fee?
Keep the total at Rs 40 crore. The management fee falls to Rs 10 crore, so the performance fee must bring in Rs 30 crore, and it is charged on a gain of Rs 110 crore, not Rs 100 crore. 30 divided by 110 is 27.3%. The base grows because less has been taken off the top before the performance fee is worked out. State the assumptions as you go: no hurdle rate, and no earlier losses to recover below a high-water markThe highest value an investor has paid a performance fee on; no new performance fee is charged until the fund climbs back above it..
The relationship40 the manager's total fee income under 2 and 20, Rs crore 10 the new 1% management fee, Rs crore 120 the gross gain, 12% of Rs 1,000 crore What it says in wordsThe new performance fee is the income still needed, divided by the gain left after the new management fee.Is the new deal really the same for investors?
Only at a 12% gross return. The new deal pays the manager less in poor years and more in good ones, so it moves risk from the investors to the manager. At a 4% gross return the old deal pays Rs 24 crore and the new one Rs 18.2 crore; at 20% the old pays Rs 56 crore and the new one Rs 61.8 crore. That is why allocators push for a lower fixed fee even at the price of a higher share: they would rather pay for performance than for size.
Gross return 2 and 20, Rs crore 1 and 27.3, Rs crore Who gains from the switch 4% 24.0 18.2 Investors 12% 40.0 40.0 Neither 20% 56.0 61.8 Manager Manager's fee income on Rs 1,000 crore under each deal: the two match at a 12% gross return, the new deal pays Rs 5.8 crore less at 4% and Rs 5.8 crore more at 20%. Where candidates lose it
The common slip is 30%: dividing the Rs 30 crore needed by the old Rs 100 crore base, forgetting that a smaller management fee leaves a larger gain for the performance fee to work on. The other is 25%, dividing by the gross Rs 120 crore.
The second loss is stopping at 27.3% as though the two deals were identical. They match only at a 12% return, and the interviewer wants to hear who comes out ahead in good years and in bad ones.
What the interviewer asks next
- At what gross return does the manager prefer the new deal?
- Add a 5% hurdle to the new deal. What performance fee keeps the manager whole now?
- How does a high-water mark change what the performance fee is worth to the manager?
Asked at Two Sigma, Equity Capital Markets, New York, 2026 (Wall Street Oasis):
the 2/20 rule, and if one part of this equation changed, how would the other variable make up for it
