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Equity Decomposition: Understanding Your P&L Drivers

Practice—Process·Trading Analytics
February 5, 20258 min read

An equity curve going up is encouraging. But it tells you nothing about why it is going up—or what might cause it to stop. Equity decomposition breaks your P&L into its component parts so you can see exactly which drivers contribute to your bottom line.

What Is Equity Decomposition?

Traditional equity curves show a single line: your cumulative P&L over time. Equity decomposition separates that line into layers, each representing a different driver of performance. Think of it as an X-ray of your equity curve.

Practice—Process decomposes your P&L by:

  • Strategy: Which trading approaches contribute most
  • Instrument: Which markets are driving returns
  • Session type: Morning, afternoon, or overnight
  • Trade direction: Long versus short contributions
  • Risk management: How much stops are saving (or costing) you
  • The Waterfall Chart

    The primary visualisation is a waterfall chart that shows how each component adds to or subtracts from your total P&L. Green bars represent positive contributions; red bars represent negative contributions. The cumulative result equals your total return.

    This immediately highlights:

  • Which strategy is your primary profit driver
  • Which instruments are net negatives in your book
  • Whether your short trades are adding value or acting as a drag
  • How much fees and slippage are eroding your gross returns
  • Strategy Decomposition

    When you trade multiple strategies, it is critical to understand which ones earn their allocation. The strategy decomposition view shows:

    Contribution by Strategy

    A stacked area chart where each colour represents a strategy. If your "breakout" strategy accounts for 80% of profits but only 30% of trades, you should consider reallocating capital toward it.

    Risk-Adjusted Contribution

    Raw P&L can be misleading if one strategy uses more capital. The risk-adjusted view normalises each strategy's contribution by the capital deployed, showing return per unit of risk.

    Correlation Between Strategies

    Strategies that contribute during different market conditions provide genuine diversification. The decomposition highlights whether your strategies are complementary or redundant.

    Instrument Decomposition

    Breakdown by instrument reveals:

  • Top contributors: The instruments generating most of your profit
  • Persistent losers: Instruments you consistently lose money on
  • High variance: Instruments with large swings that introduce risk without proportional return
  • If an instrument has been a net negative across 50 or more trades, the data suggests removing it from your watchlist—regardless of how well you think you understand it.

    Temporal Decomposition

    Time-based decomposition reveals how profits distribute across:

  • Day of week: Some traders consistently lose on Mondays and profit on Wednesdays
  • Time of day: Morning versus afternoon performance
  • Market conditions: Trending versus ranging periods
  • Calendar effects: Around economic releases, earnings seasons, or option expiry
  • Fee and Slippage Impact

    Often overlooked, fees and slippage can be the difference between profitability and breakeven. The fee decomposition layer shows:

  • Total fees paid over any period
  • Fees as a percentage of gross profit
  • Average fee per trade by broker and instrument
  • Estimated slippage based on limit versus market order fill rates
  • Using Decomposition for Decisions

    Capital Allocation

    If Strategy A contributes 60% of profits with 2% of drawdown while Strategy B contributes 15% of profits with 40% of drawdown, the allocation decision becomes clear. Let the decomposition guide where your capital works hardest.

    Pruning Underperformers

    The decomposition often reveals that removing your worst instrument or strategy would have improved overall returns. Test this hypothesis by filtering it out and observing the impact on your equity curve.

    Identifying Regime Changes

    When a previously strong strategy shifts from green to red in the decomposition, it signals a regime change. This is an early warning to reduce exposure before the drawdown deepens.

    Navigate to Analytics then Equity Decomposition to see exactly what is driving your P&L—and what is holding it back.

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    Practice—Process
    Trading Analytics

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