Comprehensive Guide
Learn more in our Investing Guide.
How it works
Risk parity allocates by RISK contributed rather than dollars committed: instead of 60% of capital, stocks get whatever weight makes them contribute 60% of... nothing — the point is EQUAL risk contributions from every sleeve. Full implementations solve constrained optimizations; this sketcher uses the classic shortcut, inverse-volatility weighting, where each asset's weight is proportional to one divided by its volatility. Low-vol bonds consequently dominate capital — an 18/6/15 trio lands near 17/52/31 — because equalizing risk from calm assets requires owning much more of them. The result is estimated with a uniform-correlation approximation of portfolio variance, set against a static 60/40 of the same ingredients so the diversification effect has a reference point. Honest caveats belong in every sentence about this approach: inverse-vol weights only approximately equalize risk contributions when correlations differ; unlevered versions accept lower EXPECTED returns than stock-heavy mixes (true institutional parity levers bonds up); and a single average-correlation number flattens the correlation spikes that define crises. Treat output as a thinking scaffold for allocation conversations, not a tradable recipe.Formula
wi ∠1/σi (normalized) | σp² ≈ Ï(Σ wiσi)² + (1−Ï) Σ wi²σi² | Compare against 60/40 of the same assets
Tips
- Expect bond-heavy weights — that IS the strategy, not a bug.
- Unlevered parity trades expected return for smoother rides; size expectations accordingly.
- Test correlation spikes: raise the average to 50% and watch the advantage shrink.
- Real risk parity optimizes contributions; treat inverse-vol as its quick cousin.
- Rebalance periodically — volatilities drift and weights follow them.
Frequently asked questions
What is risk parity investing in simple terms?
Allocating so each asset contributes EQUALLY to portfolio risk instead of allocating capital equally. Because bonds wiggle far less than stocks, that means owning much more of them — often 50–70% — sometimes with leverage lifting returns back up. The goal is a smoother, more balanced ride.
How do inverse-volatility weights work?
Each weight equals one over the asset's volatility, normalized across holdings. Stocks at 18% vol and bonds at 6% produce a 1:3 raw ratio — 25/75 before adjustments. It approximates equal risk contribution when correlations are similar and is the standard quick proxy for full parity optimization.
Why do risk-parity portfolios hold so many bonds?
Because risk, not dollars, is being balanced. Bonds at 6% volatility carry a third of stocks' 18%, so equalizing contributions requires several times their capital — often 50–70% of the portfolio. Institutional versions then borrow to scale returns back up; unlevered versions accept lower expected growth.
Did risk parity work in 2022 when stocks and bonds fell together?
Poorly — the strategy leans on negative stock/bond correlation that flipped positive as rates spiked, and classic parity mixes drew down on the order of 15% (illustrative). It cushioned equity crashes historically but cannot protect against synchronized inflation-driven selloffs; correlation assumptions are the fragile ingredient.
Is inverse-vol weighting the same as true risk parity?
Not exactly. True parity solves for weights making each asset's marginal risk contribution equal; inverse-vol approximates that quickly. An 18%-vol stock against 6%-vol bonds gets a 1:3 raw ratio either way, but results diverge when pairwise correlations differ widely — close cousins, not twins.