Equal Risk Contribution (ERC)
Equal risk contribution (ERC) is a portfolio construction approach that allocates weights such that each asset contributes an identical share of the total portfolio risk, irrespective of its expected return — also known as the risk parity approach applied at the asset level.
ERC portfolios address a fundamental asymmetry in traditional portfolios: in a typical 60/40 equity-bond portfolio, equities may account for 60% of capital but over 90% of total portfolio volatility, because equities are far more volatile than bonds. ERC rebalances risk rather than capital, ensuring each constituent asset contributes equally to portfolio variance.
The marginal contribution to risk (MCR) of asset i is defined as: MCR_i = (∂σ_p / ∂w_i) = (Σw)_i / σ_p, where Σ is the covariance matrix and σ_p is total portfolio volatility. The total risk contribution (TRC) of asset i is w_i × MCR_i. An ERC portfolio requires w_i × MCR_i = w_j × MCR_j for all i, j — that is, equal dollar risk contribution from every asset.
In practice, solving for ERC weights requires numerical optimisation since no closed-form solution exists. The resulting portfolio typically places less weight on high-volatility assets (equities) and more on low-volatility assets (bonds, gold), resembling a risk parity allocation. At the extreme, in a two-asset equity-bond portfolio, ERC would hold approximately 25% equity and 75% bonds if equity volatility is three times bond volatility.
In India, ERC-style thinking gained prominence as multi-asset fund managers recognised the volatility imbalance in typical domestic portfolios. Funds that incorporated gold and short-duration bonds alongside equities found that equalising risk contributions from these three asset classes produced smoother drawdown profiles over the 2015–2020 period, which included demonetisation (November 2016), IL&FS liquidity crisis (2018), and the COVID crash (2020).
SEBI-registered AIF Category III funds and some PMS providers offering quantitative strategies began reporting risk contributions per position as part of client portfolio analytics. ERC is particularly appealing for investors who struggle to form return expectations but have more confidence in relative volatility assessments.