Volatility Drag: The Hidden Cost
The Hidden Cost: Volatility Drag
Volatility isn't just risk — it automatically reduces returns through a mechanism called volatility drag.
Example:
- A stock with 20% annual volatility loses ~2% of returns per year, even with zero trend
- A stock with 50% volatility loses ~12.5% per year
This explains why low-volatility portfolios often outperform high-volatility ones (all else equal).
The automatic return reduction from volatility, regardless of skill. For σ=20%, drag = -2% per year. This is from the compounding effect of return variance.
High volatility periods cluster — they don't arrive randomly. This means today's high vol predicts tomorrow's high vol. Critical for forecasting risk and sizing positions.
A stock has 30% annual volatility and 0% expected return. What's the approximate volatility drag?
Volatility drag: -σ²/2 automatically reduces returns (math, not luck)
Example: 20% vol → -2% annual drag. 50% vol → -12.5% drag
Implication: Prefer low-vol strategies, all else equal
Volatility clustering: high-vol periods tend to persist (use for forecasting)
Key for practice: Forecast vol to size positions (high vol → smaller positions)