The iShares MSCI USA Size Factor ETF (SIZE) seeks to track the MSCI USA Risk Weighted Index, which measures the performance of U.S. large- and mid-cap stocks weighted by the inverse of their risk rather than market capitalization. This factor-based equity ETF provides exposure to lower-volatility American companies across all sectors.
How It Works
SIZE uses a passively managed, risk-weighted approach that assigns higher allocations to stocks with lower historical volatility and smaller weights to more volatile securities. The fund rebalances semi-annually in May and November to maintain alignment with risk characteristics. Unlike traditional market-cap weighted ETFs, this strategy can result in significant sector tilts toward historically stable industries like utilities and consumer staples while underweighting volatile sectors like technology.
Key Features
- Risk-weighted methodology reduces portfolio volatility by up to 20% compared to market-cap weighted U.S. equity ETFs
- Zero expense ratio makes it one of the lowest-cost factor ETFs available for accessing low-volatility strategies
- Systematic rebalancing captures volatility premiums by selling high-volatility stocks and buying stable performers
Risks
- This ETF can underperform during momentum-driven bull markets when high-volatility growth stocks lead, potentially lagging by 5-10% annually
- Risk-weighting methodology may create unintended sector concentrations, with defensive sectors comprising 40-50% of holdings during volatile periods
- Factor strategies can experience multi-year periods of underperformance when market preferences shift toward growth over stability
Who Should Own This
Best suited as a satellite holding (10-25% of equity allocation) for conservative investors with 3+ year time horizons seeking reduced portfolio volatility. Low-to-medium risk tolerance required. Ideal for investors approaching retirement or those wanting equity exposure with lower drawdowns than traditional market-cap weighted funds.