Quant interview prep guides

Mean Reversion Signal Interview Guide

Mean reversion signal interview guide covering signal definition, horizon, z-scores, costs, regimes, examples, and failure modes.

Candidates designing and evaluating reversal or spread signals.

Mean reversion bets on correction

A mean-reversion signal assumes a price, spread, return, or residual has moved away from a reference level and may move back.

The reference level matters

Rolling means, residual models, fair-value estimates, and peer relationships each define a different notion of normal behavior.

Concrete example

A spread two standard deviations above its rolling mean may trigger a short-spread trade if historical behavior and costs support it.

Regime shifts break reversion

A deviation can reflect new information, structural change, liquidity stress, or crowding rather than temporary noise in prices.

Common mistakes

Candidates often buy every dip. Strong answers ask whether the move is noise, information, or a broken model assumption.

Practice the pattern

Use the LeetQuidity curriculum and calibration to turn this topic into a focused practice plan.