VIIIX vs. SPY

Last updated Jun 20, 2026

VIIIX (Vanguard Institutional Index Fund Institutional Plus Shares) and SPY (State Street SPDR S&P 500 ETF) are both S&P 500 funds tracking the S&P 500 Index, from Vanguard and State Street respectively. Both are passively managed. Over the past 10 years, VIIIX returned 15.65%/yr vs 15.48%/yr for SPY. With a 0.98 correlation, they move nearly in lockstep. VIIIX charges 0.02%/yr vs 0.09%/yr for SPY.

Performance

VIIIX vs. SPY - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) and State Street SPDR S&P 500 ETF (SPY). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both stocks are quite close, with VIIIX having a 10.19% return and SPY slightly lower at 10.09%. Both investments have delivered pretty close results over the past 10 years, with VIIIX having a 15.65% annualized return and SPY not far behind at 15.48%.

VIIIX

• 1D: 1.09%
• 1M: 0.85%
• YTD: 10.19%
• 6M: 10.40%
• 1Y: 27.18%
• 3Y*: 21.39%
• 5Y*: 14.24%
• 10Y*: 15.65%

SPY

• 1D: 1.04%
• 1M: 0.80%
• YTD: 10.09%
• 6M: 10.30%
• 1Y: 27.05%
• 3Y*: 20.82%
• 5Y*: 14.00%
• 10Y*: 15.48%

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

VIIIX vs. SPY - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	10.19%	17.87%	26.29%	25.79%	-18.14%	28.69%	18.41%	31.48%	-4.41%	21.82%
SPY State Street SPDR S&P 500 ETF	10.09%	17.72%	24.89%	26.18%	-18.18%	28.73%	18.33%	31.22%	-4.57%	21.71%

Correlation

The correlation between VIIIX and SPY is 1.00 - these two move nearly in lockstep. At this level, holding both provides almost no diversification benefit. If you already own one, adding the other does little to reduce portfolio risk.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	1.00
Correlation (3Y) Calculated over the trailing 3-year period	1.00
Correlation (5Y) Calculated over the trailing 5-year period	1.00
Correlation (10Y) Calculated over the trailing 10-year period	1.00
Correlation (All Time) Calculated using the full available price history since Jul 7, 1997	0.98

The correlation between VIIIX and SPY has been stable across timeframes, ranging from 0.98 to 1.00 - a consistent structural relationship.

VIIIX vs. SPY - Sectors Allocation Comparison

Sectors	VIIIX	SPY
Technology	35.7%	39.0%
Financial Services	11.6%	11.1%
Communication Services	11.3%	10.6%
Consumer Cyclical	10.2%	9.9%
Healthcare	8.5%	8.3%
Industrials	8.3%	7.8%
Consumer Defensive	4.9%	4.5%
Energy	3.5%	3.1%
Utilities	2.4%	2.1%
Real Estate	1.9%	1.8%
Basic Materials	1.8%	1.7%

Return for Risk

VIIIX vs. SPY — Risk / Return Rank

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

VIIIX

VIIIX Risk / Return Rank: 71
VIIIX Sharpe Ratio Rank: 70
VIIIX Sortino Ratio Rank: 63
VIIIX Omega Ratio Rank: 65
VIIIX Calmar Ratio Rank: 73
VIIIX Martin Ratio Rank: 82

SPY

SPY Risk / Return Rank: 70
SPY Sharpe Ratio Rank: 71
SPY Sortino Ratio Rank: 68
SPY Omega Ratio Rank: 70
SPY Calmar Ratio Rank: 64
SPY Martin Ratio Rank: 76

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.

VIIIX vs. SPY - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) and State Street SPDR S&P 500 ETF (SPY). 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.

	VIIIX	SPY	Difference
Sharpe ratio: Return per unit of total volatility	2.17	2.17	0.00
Sortino ratio: Return per unit of downside risk	2.93	2.92	+0.01
Omega ratio: Gain probability vs. loss probability	1.39	1.39	0.00
Calmar ratio: Return relative to maximum drawdown	3.04	3.02	+0.01
Martin ratio: Return relative to average drawdown	13.74	13.61	+0.14

VIIIX vs. SPY - Sharpe Ratio Comparison

The current VIIIX Sharpe Ratio is 2.17, which is comparable to the SPY Sharpe Ratio of 2.17. The chart below compares the historical Sharpe Ratios of VIIIX and SPY, 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

VIIIX vs. SPY - Drawdown Comparison

The maximum VIIIX drawdown since its inception was -55.18%, roughly equal to the maximum SPY drawdown of -55.19%. Use the drawdown chart below to compare losses from any high point for VIIIX and SPY.

Drawdown Indicators

	VIIIX	SPY	Difference
Max Drawdown Largest peak-to-trough decline	-55.18%	-55.19%	+0.01%
Max Drawdown (1Y) Largest decline over 1 year	-8.90%	-8.88%	-0.02%
Max Drawdown (3Y) Largest decline over 3 years	-18.75%	-18.76%	+0.01%
Max Drawdown (5Y) Largest decline over 5 years	-24.50%	-24.50%	0.00%
Max Drawdown (10Y) Largest decline over 10 years	-33.79%	-33.72%	-0.07%
Current Drawdown Current decline from peak	-1.36%	-1.44%	+0.08%
Average Drawdown Average peak-to-trough decline	-10.00%	-9.04%	-0.96%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.96%	1.97%	-0.01%

Volatility

VIIIX vs. SPY - Volatility Comparison

Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) and State Street SPDR S&P 500 ETF (SPY) have volatilities of 4.77% and 4.73%, respectively, indicating that both stocks experience similar levels of price fluctuations. This suggests that the risk associated with both stocks, as measured by volatility, is nearly the same. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VIIIX	SPY	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.77%	4.73%	+0.04%
Volatility (6M) Calculated over the trailing 6-month period	9.91%	9.81%	+0.10%
Volatility (1Y) Calculated over the trailing 1-year period	12.47%	12.41%	+0.06%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	16.99%	17.15%	-0.16%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.10%	17.98%	+0.12%

VIIIX vs. SPY - Expense Ratio Comparison

VIIIX has a 0.02% expense ratio, which is lower than SPY's 0.09% expense ratio. Despite the difference, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

VIIIX vs. SPY - Dividend Comparison

VIIIX's dividend yield for the trailing twelve months is around 2.44%, more than SPY's 1.24% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
SPY State Street SPDR S&P 500 ETF	1.01%	1.07%	1.21%	1.40%	1.65%	1.20%	1.52%	1.75%	2.04%	1.80%	2.03%	2.06%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	2.44%	2.11%	3.66%	2.66%	3.39%	4.79%	3.07%	2.86%	2.45%	1.84%	2.38%	2.47%

Frequently Asked Questions

Can I hold both VIIIX and SPY in my portfolio?

With a correlation of 1.00, VIIIX and SPY move almost identically. Holding both adds very little diversification - you're essentially doubling your position in the same market segment. Choosing one is usually more capital-efficient.

Which is riskier, VIIIX or SPY?

VIIIX has higher volatility (4.77%) compared to SPY (4.73%). In terms of maximum drawdown, VIIIX dropped -55.18% vs SPY's -55.19%.

Which has better risk-adjusted returns?

VIIIX currently has the higher Sharpe Ratio (2.17 vs 2.17), 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.