PDT Partners Interview Questions
53 PDT Partners questions spanning probability, statistics, regression, stochastic processes, time-series, ML, linear algebra, and clean algorithmic coding.
Inside the PDT Partners interview
PDT Partners is an elite systematic quantitative hedge fund spun out of Morgan Stanley's Process Driven Trading group, where signals are built from data and held to statistical scrutiny. Its interviews run deep on probability and statistics, regression and time-series modeling, applied machine learning, and clean algorithmic coding.
What they test
The core is a research-grade statistics and regression block: deriving the OLS estimator, ridge/LASSO closed forms, multicollinearity and variance inflation, heteroskedasticity and residual diagnostics, and the geometry of least squares. Around it sit probability and expectation puzzles (random-walk and gambler's-ruin questions, coupon collector, pattern-before-pattern), a time-series and risk strand (EWMA variance, stationarity, VaR backtesting, block bootstrap), and applied machine learning on noisy market data. A steady stream of algorithmic coding rounds out the loop.
The recurring shapes
Expect to fit and interpret a linear model from scratch and defend its assumptions: what breaks under collinearity, what shrinkage buys you, how to read coefficients and residuals. On the probability side, the shapes are stopping-time and first-passage arguments and clean expectation computations. The data problems are deliberately noisy — you are asked to find a real signal, calibrate it, and judge whether a Sharpe improvement is statistically detectable.
How to approach
Reason from first principles and say the assumptions out loud. For the stats problems, write the estimator, take the derivative, and connect the algebra to a picture (projection, eigenvalues, half-life). For probability, set up the recursion or conditioning before reaching for a formula. For coding, write correct, readable solutions with the right data structure — PDT values clean engineering as much as clever math.
The mix leans medium with a substantial hard tail in the regression, statistics, and stochastic-process sections, plus a handful of easy warm-ups.
PDT Partners coding questions (13)
- Sum of Odd Integers Up to Each Value
- Merge Two Sorted Iterators
- Maximum Root-to-Leaf Path Sum in a Binary Tree
- Maximum Difference With the Larger Element on the Right
- Design a SuperStack With a Bulk-Increment Operation
- Add Two Numbers (Linked List)
- Implement a Reference-Counted Smart Pointer in C++
- Avoiding the Monsters
- Split Array to Minimize the Largest Subarray Sum
- Streaming Top-K Sum With Updates
- All-Pairs Two-Sum With Stable Ordering
- Decode Number String
- Maximum Profit from ETF Premium Trading
PDT Partners probability questions (8)
- Five Heads in a Row -- Is the Coin Fair?
- Probability of HTH Before HHT
- Optimal Position for the Birthday Match
- The Gaussian Integral
- Generate Uniform 1-7 from Uniform 1-5
- Break-Even Price of a Digital with Two Independent Signals
- Most Likely Position of the First Ace
- Angle Distribution in a Random Right Triangle
PDT Partners statistics questions (8)
- Breusch-Pagan Heteroskedasticity Test
- Power and Sample Size for Sharpe Ratio Detection
- Scoring Rules and Model Calibration for Trading Classifiers
- VaR Backtesting: Kupiec and Christoffersen Tests
- Optimal Estimate from Two Scales
- Order Statistics and Inverse Transform Sampling
- KMV Distinct Counting
- Finding the Story in Employee Productivity Data
PDT Partners regression questions (6)
PDT Partners machine learning questions (5)
PDT Partners expected value questions (4)
PDT Partners linear algebra questions (3)
PDT Partners time series questions (3)
PDT Partners combinatorics questions (2)
PDT Partners stochastic processes questions (1)
PDT Partners interview FAQ
What kind of questions does PDT Partners ask in quant interviews?
Candidates most often report coding, probability and statistics questions. This page collects 53 of them, 10 stamped with the month they were last reported — each with a full worked solution.
How hard are PDT Partners interview questions?
The set spans 9 easy, 28 medium and 16 hard problems. Most sit at medium difficulty — solvable in a few minutes with clean reasoning — with a harder tail that rewards knowing the canonical tricks.
How do I prepare for the PDT Partners quant interview?
Work through this set by topic (use the sidebar), starting from your weakest area. 3 problems are free to open with their full solution, so you can judge the quality before anything else. Then walk the full PDT Partners interview guide for the round-by-round funnel and the online assessment.
Are these the actual PDT Partners interview questions?
They are built from candidate-reported PDT Partners questions. We rewrite each prompt for clarity and author the worked solutions ourselves — we don't claim the wording is verbatim, and we never invent questions or recycle generic lists. 10 of 53 carry the month they were last reported.