P&L and Performance Attribution Explained

P&L and Performance Attribution

Performance attribution explains where returns came from: allocation, selection, factors, Greeks and costs. Learn Brinson attribution, P&L explain and how to use it.

Advanced3 min readUpdated 3 Oct 2026

Lesson 35 of 44

Knowing that a portfolio returned 9% is only the start. Performance attribution breaks that return into its sources: how much came from the market, from sector choices, from individual stock picks, from factor exposures, from currency moves or from trading costs. On trading desks, the equivalent is P&L explain, which splits daily profit and loss into the effects of price moves, volatility, time decay and new trades. Attribution separates skill from luck and intended bets from accidental ones.

Brinson attribution#

The Brinson model, from work by Gary Brinson and coauthors in the 1980s, splits active return versus a benchmark into:

Effect	Question
Allocation	Did overweighting or underweighting sectors help?
Selection	Did the stocks chosen within each sector beat that sector?
Interaction	The combined effect of weight and selection differences

Factor based attribution#

Factor attribution explains returns by exposure to factors such as market, size, value, momentum and industry. The part not explained by factors is the specific return, a closer measure of stock picking skill. See Factor Models and Alpha and Beta.

P&L explain for trading desks#

Component	Source
Delta P&L	Moves in the underlying price
Gamma P&L	Convexity from larger moves. See Gamma
Vega P&L	Changes in implied volatility. See Vega
Theta P&L	Passage of time. See Theta
Rates and carry	Interest and funding effects
New trade P&L	Profit from trades executed today, such as spread capture
Unexplained	Residual that may signal model or data problems

A large unexplained P&L is a warning sign that risk models or position records may be wrong, and it is investigated by risk and product control teams. See Risk Analyst.

Attribution for traders#

Individual traders can attribute results by:

Breakdown	Insight
Strategy or setup	Which setups make money. See Trading Journal
Instrument	Where you have an edge
Long versus short	Directional bias
Time of day or market regime	When the strategy works. See Structural Breaks and Regime Changes
Entry versus exit quality	Whether exits give back profits. See MAE and MFE
Costs	How much commissions and slippage take. See Slippage Analysis

Pitfalls#

Wrong benchmark, making allocation and selection meaningless.
Short periods, where luck dominates. See Statistical Significance in Trading.
Ignoring costs and currency effects.
Different models giving different answers; state the method used.
Using attribution to justify rather than to learn.

Making attribution a habit#

Run attribution on a fixed schedule, such as monthly, using the same method and benchmark each time, so results are comparable. Keep a short written note of what the numbers show and what you will change, then check next month whether the change helped.

Frequently asked questions#

What is performance attribution?#

The analysis of where a portfolio's returns came from, such as asset allocation, security selection, factor exposures, currency and costs.

What is the Brinson model?#

A method that splits active return into allocation, selection and interaction effects relative to a benchmark.

What is P&L explain?#

A breakdown of a trading desk's daily profit and loss into price, volatility, time, carry and new trade effects, with an unexplained residual.

Next, learn what happens after a trade is executed in Clearing, Settlement and Custody.

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Next lessonClearing, Settlement and CustodyAfter a trade, clearing confirms and guarantees it, settlement exchanges cash and securities and custody holds assets safely. Learn the process, T+1 and key players.