SIZE vs. VOO

Last updated Jun 24, 2026

SIZE (iShares MSCI USA Size Factor ETF) and VOO (Vanguard S&P 500 ETF) are both exchange-traded funds - SIZE is a Mid Cap Blend Equities fund tracking the MSCI USA Low Size Index, while VOO is a S&P 500 fund tracking the S&P 500 Index. Both are passively managed. Over the past 10 years, SIZE returned 12.00%/yr vs 15.61%/yr for VOO. Their correlation of 0.84 suggests significant overlap in exposure. SIZE charges 0.15%/yr vs 0.03%/yr for VOO.

Performance

SIZE vs. VOO - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in iShares MSCI USA Size Factor ETF (SIZE) and Vanguard S&P 500 ETF (VOO). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, SIZE achieves a 8.82% return, which is significantly higher than VOO's 8.19% return. Over the past 10 years, SIZE has underperformed VOO with an annualized return of 12.00%, while VOO has yielded a comparatively higher 15.61% annualized return.

SIZE

• 1D: -0.38%
• 1M: 0.73%
• YTD: 8.82%
• 6M: 7.67%
• 1Y: 17.11%
• 3Y*: 15.52%
• 5Y*: 7.90%
• 10Y*: 12.00%

VOO

• 1D: -1.42%
• 1M: -1.34%
• YTD: 8.19%
• 6M: 7.24%
• 1Y: 23.69%
• 3Y*: 20.78%
• 5Y*: 13.13%
• 10Y*: 15.61%

*Multi-year figures are annualized to reflect compound growth (CAGR)

SIZE vs. VOO - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
SIZE iShares MSCI USA Size Factor ETF	8.82%	10.51%	14.37%	17.78%	-15.86%	25.05%	16.26%	28.97%	-6.59%	18.76%
VOO Vanguard S&P 500 ETF	8.19%	17.82%	24.98%	26.32%	-18.17%	28.79%	18.32%	31.37%	-4.50%	21.77%

Correlation

The correlation between SIZE and VOO is 0.76, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.76
Correlation (3Y) Calculated over the trailing 3-year period	0.82
Correlation (5Y) Calculated over the trailing 5-year period	0.89
Correlation (10Y) Calculated over the trailing 10-year period	0.89
Correlation (All Time) Calculated using the full available price history since Apr 18, 2013	0.84

The correlation between SIZE and VOO shifts across timeframes, from 0.76 (1 year) to 0.89 (10 years), reflecting how their relationship changes across market environments.

SIZE vs. VOO - Sectors Allocation Comparison

Sectors	SIZE	VOO
Technology	20.0%	39.1%
Industrials	15.3%	7.6%
Financial Services	14.7%	10.9%
Consumer Cyclical	11.2%	9.8%
Healthcare	10.7%	8.3%
Utilities	5.4%	2.5%
Consumer Defensive	5.3%	4.5%
Real Estate	5.3%	1.8%
Basic Materials	4.3%	1.7%
Communication Services	3.9%	10.5%
Energy	3.7%	3.2%

Return for Risk

SIZE vs. VOO — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.

SIZE

SIZE Risk / Return Rank: 43
SIZE Sharpe Ratio Rank: 39
SIZE Sortino Ratio Rank: 40
SIZE Omega Ratio Rank: 37
SIZE Calmar Ratio Rank: 46
SIZE Martin Ratio Rank: 52

VOO

VOO Risk / Return Rank: 59
VOO Sharpe Ratio Rank: 59
VOO Sortino Ratio Rank: 56
VOO Omega Ratio Rank: 58
VOO Calmar Ratio Rank: 56
VOO Martin Ratio Rank: 67

The rank (0–100) shows how this investment's returns compare to the risk taken. Higher = better. Based on the past 12 months of data, combining Sharpe, Sortino, and other metrics used by quantitative funds and institutional investors.

SIZE vs. VOO - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for iShares MSCI USA Size Factor ETF (SIZE) and Vanguard S&P 500 ETF (VOO). Risk-adjusted metrics are performance indicators that assess an investment's returns in relation to its risk, enabling a more accurate comparison of different investment options.

Values are calculated on a 1-year rolling basis and updated daily. Risk-adjusted metrics are more stable over longer periods — use the period switch above to explore them.

	SIZE	VOO	Difference
Sharpe ratio: Return per unit of total volatility	1.33	1.91	-0.59
Sortino ratio: Return per unit of downside risk	1.96	2.60	-0.64
Omega ratio: Gain probability vs. loss probability	1.23	1.35	-0.11
Calmar ratio: Return relative to maximum drawdown	2.16	2.67	-0.52
Martin ratio: Return relative to average drawdown	8.33	11.96	-3.63

SIZE vs. VOO - Sharpe Ratio Comparison

The current SIZE Sharpe Ratio is 1.33, which is lower than the VOO Sharpe Ratio of 1.91. The chart below compares the historical Sharpe Ratios of SIZE and VOO, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Drawdowns

SIZE vs. VOO - Drawdown Comparison

The maximum SIZE drawdown since its inception was -39.15%, which is greater than VOO's maximum drawdown of -33.99%. Use the drawdown chart below to compare losses from any high point for SIZE and VOO.

Drawdown Indicators

	SIZE	VOO	Difference
Max Drawdown Largest peak-to-trough decline	-39.15%	-33.99%	-5.16%
Max Drawdown (1Y) Largest decline over 1 year	-7.97%	-8.90%	+0.93%
Max Drawdown (3Y) Largest decline over 3 years	-18.71%	-18.69%	-0.02%
Max Drawdown (5Y) Largest decline over 5 years	-24.03%	-24.52%	+0.49%
Max Drawdown (10Y) Largest decline over 10 years	-39.15%	-33.99%	-5.16%
Current Drawdown Current decline from peak	-1.59%	-3.14%	+1.55%
Average Drawdown Average peak-to-trough decline	-4.17%	-3.68%	-0.49%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.06%	1.99%	+0.07%

Volatility

SIZE vs. VOO - Volatility Comparison

The current volatility for iShares MSCI USA Size Factor ETF (SIZE) is 3.87%, while Vanguard S&P 500 ETF (VOO) has a volatility of 4.83%. This indicates that SIZE experiences smaller price fluctuations and is considered to be less risky than VOO based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	SIZE	VOO	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.87%	4.83%	-0.96%
Volatility (6M) Calculated over the trailing 6-month period	9.83%	9.82%	+0.01%
Volatility (1Y) Calculated over the trailing 1-year period	12.98%	12.46%	+0.52%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.43%	16.91%	+0.52%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.70%	18.02%	+0.68%

SIZE vs. VOO - Expense Ratio Comparison

SIZE has a 0.15% expense ratio, which is higher than VOO's 0.03% expense ratio. However, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

SIZE vs. VOO - Dividend Comparison

SIZE's dividend yield for the trailing twelve months is around 1.40%, more than VOO's 1.05% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
SIZE iShares MSCI USA Size Factor ETF	1.40%	1.50%	1.53%	1.42%	1.59%	1.19%	1.43%	1.35%	2.43%	1.58%	1.88%	1.95%
VOO Vanguard S&P 500 ETF	1.05%	1.13%	1.24%	1.46%	1.69%	1.25%	1.54%	1.88%	2.06%	1.78%	2.02%	2.10%

Frequently Asked Questions

Can I hold both SIZE and VOO in my portfolio?

SIZE and VOO have a correlation of 0.76, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, SIZE or VOO?

VOO has higher volatility (4.83%) compared to SIZE (3.87%). In terms of maximum drawdown, SIZE dropped -39.15% vs VOO's -33.99%.

Which ETF is better, SIZE or VOO?

On 10-year performance, VOO leads with 15.61% vs 12.00% for SIZE. On fees, VOO is cheaper at 0.03% per year. On volatility, SIZE has been the lower-risk option at 3.87%. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF has performed better, SIZE or VOO?

Over the 10-year period, VOO has performed better with a 15.61% return vs 12.00%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

Which ETF is cheaper, SIZE or VOO?

VOO is cheaper with a 0.03% expense ratio, compared with 0.15% for SIZE.

Which ETF pays a higher dividend yield, SIZE or VOO?

SIZE has the higher dividend yield at 1.40%, compared with 1.05% for VOO.

What is the main difference between SIZE and VOO?

SIZE is categorized as Mid Cap Blend Equities, while VOO is S&P 500. SIZE tracks MSCI USA Low Size Index, while VOO tracks S&P 500 Index. They also come from different issuers: iShares and Vanguard. Their fees differ too: 0.15% for SIZE and 0.03% for VOO.

Which has better risk-adjusted returns?

VOO currently has the higher Sharpe Ratio (1.91 vs 1.33), meaning it's delivered slightly more return per unit of risk over the trailing 12 months. However, this ranking shifts over time - use the Risk/Return Score above for a more comprehensive view that combines Sharpe, Sortino, and other measures used by quantitative funds.