PnL Breakdown & Custom Composite Benchmarks
Institutional standards for decomposing net portfolio performance into 4 independent sources and constructing custom composite benchmarks.
1. PnL Breakdown Engine
Traditional retail tools reduce performance to a single net PnL figure. In institutional portfolio management inspired by GAMA Infostroy, total return is decomposed into 4 components:
$$\text{Total PnL} = \text{Asset PnL} + \text{FX PnL} + \text{Yield Income} - \text{Costs}$$
Where:
- $\text{Asset PnL}$ — capital gain or loss from asset price movements in native currency.
- $\text{FX PnL}$ — gain or loss from foreign currency fluctuations against base currency.
- $\text{Yield Income}$ — passive income received from dividends and bond coupons.
- $\text{Costs}$ — total trading fees, custody expenses, and tax withholdings.
2. Custom Composite Benchmarks
Comparing a multi-asset portfolio against a single index is insufficient. Composite benchmarks allow weighted combinations of base indices:
$$R_{\text{composite}} = \sum_{i=1}^{n} w_i \cdot R_i, \quad \sum_{i=1}^{n} w_i = 1$$
Where $\alpha = R_{\text{portfolio}} - R_{\text{composite}}$ evaluates portfolio excess return (Alpha).