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SIZE vs. VOO
Performance
Return for Risk
Drawdowns
Volatility
Dividends

SIZE vs. VOO

Last updated Aug 2, 2026
Documentation

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 11.70%/yr vs 15.14%/yr for VOO. Their correlation of 0.84 means they have usually moved in the same direction. 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.

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Returns By Period

In the year-to-date period, SIZE achieves a 11.20% return, which is significantly higher than VOO's 10.16% return. Over the past 10 years, SIZE has underperformed VOO with an annualized return of 11.70%, while VOO has yielded a comparatively higher 15.14% annualized return.

SIZE

1D
-0.35%
1M
0.26%
6M
8.60%
YTD
11.20%
1Y
17.37%
3Y*
13.59%
5Y*
7.99%
10Y*
11.70%
ALL TIME*
11.92%

VOO

1D
0.71%
1M
0.26%
6M
8.58%
YTD
10.16%
1Y
21.58%
3Y*
19.42%
5Y*
12.83%
10Y*
15.14%
ALL TIME*
14.78%
*Multi-year figures are annualized to reflect compound growth (CAGR)

Liquidity Comparison

PositionAvg. Volume Value (2W)Avg. Volume Value (1M)Avg. Volume Value (3M)

SIZE

iShares MSCI USA Size Factor ETF
$662.14K$788.99K$1.01M

VOO

Vanguard S&P 500 ETF
$3.82B$3.78B$5.44B

SIZE vs. VOO - Yearly Performance Comparison

2026 (YTD)202520242023202220212020201920182017
SIZE
iShares MSCI USA Size Factor ETF		11.20%10.51%14.37%17.78%-15.86%25.05%16.26%28.97%-6.59%18.76%
VOO
Vanguard S&P 500 ETF		10.16%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 0.73, which is moderate. They have sometimes moved together and sometimes differently, sharing some price drivers without tracking each other closely.

Correlation
Correlation (1Y)
Focuses on recent behavior, but can change the most.

0.73

Correlation (3Y)
Balances recent behavior with more history.

0.81

Correlation (5Y)
Shows whether the relationship held over a longer period.

0.88

Correlation (10Y)
Provides a long-term view across more market conditions.

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 0.73 (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

18.6%
38.6%

Financial Services

15.7%
11.4%

Industrials

14.8%
8.5%

Healthcare

11.4%
8.9%

Consumer Cyclical

10.9%
9.5%

Utilities

5.6%
2.2%

Consumer Defensive

5.5%
4.5%

Real Estate

5.3%
1.8%

Basic Materials

4.9%
1.7%

Energy

3.8%
3.0%

Communication Services

3.3%
9.9%

Technology

SIZE
18.6%
VOO
38.6%

Financial Services

SIZE
15.7%
VOO
11.4%

Industrials

SIZE
14.8%
VOO
8.5%

Healthcare

SIZE
11.4%
VOO
8.9%

Consumer Cyclical

SIZE
10.9%
VOO
9.5%

Utilities

SIZE
5.6%
VOO
2.2%

Consumer Defensive

SIZE
5.5%
VOO
4.5%

Real Estate

SIZE
5.3%
VOO
1.8%

Basic Materials

SIZE
4.9%
VOO
1.7%

Energy

SIZE
3.8%
VOO
3.0%

Communication Services

SIZE
3.3%
VOO
9.9%

Compare stocks, funds, or ETFs

Search for stocks, ETFs, and funds for a quick comparison or use the comparison tool for more options.

iShares MSCI USA Size Factor ETF

Vanguard S&P 500 ETF

Often compared with SIZE:
SIZE vs. XLGSIZE vs. SPYSIZE vs. QUALSIZE vs. QDVA.DESIZE vs. VIGSIZE vs. QGROSIZE vs. IJH
Often compared with VOO:
VOO vs. VTIVOO vs. QQQVOO vs. SCHDVOO vs. VTVOO vs. FXAIXVOO vs. SPYVOO vs. VGT

Return for Risk

SIZE vs. VOO — Risk / Return Rank

Compare historical risk-adjusted metric ranks over the past 12 months.
SIZE
SIZE Risk / Return Rank: 5555
Overall Rank
SIZE Sharpe Ratio Rank: 5151
Sharpe Ratio Rank
SIZE Sortino Ratio Rank: 5353
Sortino Ratio Rank
SIZE Omega Ratio Rank: 4848
Omega Ratio Rank
SIZE Calmar Ratio Rank: 5757
Calmar Ratio Rank
SIZE Martin Ratio Rank: 6565
Martin Ratio Rank
VOO
VOO Risk / Return Rank: 6868
Overall Rank
VOO Sharpe Ratio Rank: 6868
Sharpe Ratio Rank
VOO Sortino Ratio Rank: 6565
Sortino Ratio Rank
VOO Omega Ratio Rank: 6666
Omega Ratio Rank
VOO Calmar Ratio Rank: 6464
Calmar Ratio Rank
VOO Martin Ratio Rank: 7676
Martin Ratio Rank
The rank (0–100) uses a weighted average of the Sharpe, Sortino, Omega, Calmar, and Martin percentile ranks for the trailing 12 months. Higher means stronger historical risk-adjusted performance within the peer group.

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.

SIZEVOODifference
Sharpe ratioReturn per unit of total volatility
1.25
1.53

-0.28

Sortino ratioReturn per unit of downside risk
1.87
2.13

-0.26

Omega ratioGain probability vs. loss probability

1.22

1.28

-0.05

Calmar ratioReturn relative to maximum drawdown

2.02

2.21

-0.19

Martin ratioReturn relative to average drawdown

7.91

9.44

-1.52

SIZE vs. VOO - Sharpe Ratio Comparison

The current SIZE Sharpe Ratio is 1.25, which is comparable to the VOO Sharpe Ratio of 1.53. 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.

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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.

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Drawdown Indicators

SIZEVOODifference

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

-1.39%

-1.38%

-0.01%

Average Drawdown

Average peak-to-trough decline

-4.14%

-3.67%

-0.47%

Ulcer Index

Depth and duration of drawdowns from previous peaks

2.03%

2.08%

-0.05%

Volatility

SIZE vs. VOO - Volatility Comparison

The current volatility for iShares MSCI USA Size Factor ETF (SIZE) is 3.12%, while Vanguard S&P 500 ETF (VOO) has a volatility of 3.54%. 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.

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Volatility by Period

SIZEVOODifference

Volatility (1M)

Calculated over the trailing 1-month period

3.12%

3.54%

-0.42%

Volatility (6M)

Calculated over the trailing 6-month period

9.56%

10.10%

-0.54%

Volatility (1Y)

Calculated over the trailing 1-year period

12.93%

12.82%

+0.11%

Volatility (5Y)

Calculated over the trailing 5-year period, annualized

17.40%

16.93%

+0.47%

Volatility (10Y)

Calculated over the trailing 10-year period, annualized

18.67%

18.01%

+0.66%

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 1.37%, more than VOO's 1.07% yield.

PositionTTM20252024202320222021202020192018201720162015
SIZE
iShares MSCI USA Size Factor ETF		1.37%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		1.07%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

SIZE and VOO have a correlation of 0.73, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

VOO has higher volatility (3.54%) compared to SIZE (3.12%). In terms of maximum drawdown, SIZE dropped -39.15% vs VOO's -33.99%.

On 10-year performance, VOO leads with 15.14% vs 11.70% for SIZE. On fees, VOO is cheaper at 0.03% per year. On volatility, SIZE has been the lower-risk option at 3.12%. The better choice depends on whether you care most about return, fees, risk, or income.

Over the 10-year period, VOO has performed better with a 15.14% return vs 11.70%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

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

SIZE has the higher dividend yield at 1.37%, compared with 1.07% for 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.

VOO currently has the higher Sharpe Ratio (1.53 vs 1.25), 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.

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