Hedge Funds interview preparation
Long-short equity, macro, event-driven, distressed, multi-manager platforms and the Indian Category III landscape. Every question is either traced to a named firm from a public candidate report, or tagged at desk level when we could not trace it — answers lead with the point, then the mechanism, then the limitation.
100 questions, mapped to the firms that asked them
- Questions
- 100
- Traced to a firm
- 39
- Firms
- 16
- Updated
- September 2026
081Two series can be negatively correlated within each month but positively correlated over a full year. How?Squarepoint CapitalHedge Fund · Montreal · 2024
Say this
Because correlation measured within groups and correlation measured across the pooled data answer different questions. If both series share a common upward trend across months, the between-month variation is positive and can dominate the negative within-month relationship. It is Simpson's paradox in a time series.
Then walk it
- Decompose the covariance into within-group and between-group parts. Total covariance equals the average within-month covariance plus the covariance of the monthly means. Those two terms can have opposite signs, and whichever has more variance wins the pooled number.
- Concrete picture: every month, A and B move in opposite directions day to day, so within-month correlation is negative. But each month both drift higher, so the monthly averages rise together. Pool the daily data over a year and the shared drift dominates.
- The generic driver is a common slow-moving factor. Both series load positively on something persistent, such as inflation, liquidity or a market trend, while their high-frequency innovations offset. Long-horizon correlation is dominated by the common factor and short-horizon correlation by the idiosyncratic part.
- There is also a pure measurement version of this: correlation of returns is horizon dependent when returns are autocorrelated. Compute correlation on daily returns and on annual returns for the same pair and you generally get different numbers, and neither is wrong.
- Why it matters practically, which is what the interviewer is really testing: hedge ratios and diversification estimated at one horizon do not hold at another. A pair that looks hedged on daily data can be a directional bet over a year, which is exactly how a relative value book acquires an unintended factor exposure.
- So the answer to 'which correlation is right' is neither. You choose the horizon that matches your holding period and your rebalancing frequency, and you look at both to know which part of the relationship you are actually trading.
Where candidates lose it
Treating it as a paradox to be resolved rather than a decomposition to be stated. Write down the within-plus-between covariance split and the answer is immediate. And do not stop at the maths: the reason they ask is the practical consequence for hedge ratios at different horizons.
Expect next
- Which correlation would you use to set a hedge ratio?
- How does return autocorrelation affect measured correlation?
- Give me another example of Simpson's paradox in markets.
Reported by candidates at Squarepoint Capital (Hedge Fund, Montreal, 2024). Source: Wall Street Oasis.
Firm tags come from public, anonymous candidate reports on Wall Street Oasis: strong signal, not sworn testimony. Firms are named as the places a question was reported, not as partners of Fin Maverick. Answers are written for this page to show how to think out loud; they are not scripts to recite.
