PRUIX vs. VFFSX

Last updated Jun 4, 2026

PRUIX (T. Rowe Price Equity Index 500 Fund - I Class) and VFFSX (Vanguard 500 Index Fund Institutional Select Shares) are both Large Cap Blend Equities funds. Over the past 5 years, PRUIX returned 14.23%/yr vs 14.27%/yr for VFFSX. With a 0.99 correlation, they move nearly in lockstep. PRUIX charges 0.05%/yr vs 0.01%/yr for VFFSX.

Performance

PRUIX vs. VFFSX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in T. Rowe Price Equity Index 500 Fund - I Class (PRUIX) and Vanguard 500 Index Fund Institutional Select Shares (VFFSX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both investments are quite close, with PRUIX having a 11.67% return and VFFSX slightly higher at 11.71%.

PRUIX

• 1D: 0.13%
• 1M: 5.80%
• YTD: 11.67%
• 6M: 11.71%
• 1Y: 28.93%
• 3Y*: 22.70%
• 5Y*: 14.23%
• 10Y*: 15.57%

VFFSX

• 1D: 0.13%
• 1M: 5.80%
• YTD: 11.71%
• 6M: 11.74%
• 1Y: 28.99%
• 3Y*: 22.76%
• 5Y*: 14.27%
• 10Y*: —

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

PRUIX vs. VFFSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PRUIX T. Rowe Price Equity Index 500 Fund - I Class	11.67%	17.82%	24.95%	26.24%	-18.14%	28.62%	18.31%	31.63%	-4.44%	20.12%
VFFSX Vanguard 500 Index Fund Institutional Select Shares	11.71%	17.87%	25.00%	26.28%	-18.14%	29.24%	18.35%	31.88%	-4.42%	20.80%

Correlation

The correlation between PRUIX and VFFSX 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	0.98
Correlation (5Y) Calculated over the trailing 5-year period	0.99
Correlation (All Time) Calculated using the full available price history since Jan 4, 2017	0.99

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

Return for Risk

PRUIX vs. VFFSX — Risk / Return Rank

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

PRUIX

PRUIX Risk / Return Rank: 73
PRUIX Sharpe Ratio Rank: 75
PRUIX Sortino Ratio Rank: 68
PRUIX Omega Ratio Rank: 67
PRUIX Calmar Ratio Rank: 73
PRUIX Martin Ratio Rank: 83

VFFSX

VFFSX Risk / Return Rank: 73
VFFSX Sharpe Ratio Rank: 76
VFFSX Sortino Ratio Rank: 67
VFFSX Omega Ratio Rank: 67
VFFSX Calmar Ratio Rank: 74
VFFSX Martin Ratio Rank: 83

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.

PRUIX vs. VFFSX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for T. Rowe Price Equity Index 500 Fund - I Class (PRUIX) and Vanguard 500 Index Fund Institutional Select Shares (VFFSX). 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.

	PRUIX	VFFSX	Difference
Sharpe ratio: Return per unit of total volatility	2.51	2.52	0.00
Sortino ratio: Return per unit of downside risk	3.42	3.42	-0.01
Omega ratio: Gain probability vs. loss probability	1.46	1.46	0.00
Calmar ratio: Return relative to maximum drawdown	3.35	3.36	-0.01
Martin ratio: Return relative to average drawdown	15.63	15.70	-0.06
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

PRUIX vs. VFFSX - Sharpe Ratio Comparison

The current PRUIX Sharpe Ratio is 2.51, which is comparable to the VFFSX Sharpe Ratio of 2.52. The chart below compares the historical Sharpe Ratios of PRUIX and VFFSX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Sharpe Ratios by Period

	PRUIX	VFFSX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.51	2.52	0.00
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.84	0.85	-0.01
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.86	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.86	0.86	0.00

Drawdowns

PRUIX vs. VFFSX - Drawdown Comparison

The maximum PRUIX drawdown since its inception was -33.80%, roughly equal to the maximum VFFSX drawdown of -33.82%. Use the drawdown chart below to compare losses from any high point for PRUIX and VFFSX.

Drawdown Indicators

	PRUIX	VFFSX	Difference
Max Drawdown Largest peak-to-trough decline	-33.80%	-33.82%	+0.02%
Max Drawdown (1Y) Largest decline over 1 year	-8.91%	-8.90%	-0.01%
Max Drawdown (3Y) Largest decline over 3 years	-18.76%	-18.75%	-0.01%
Max Drawdown (5Y) Largest decline over 5 years	-24.52%	-24.51%	-0.01%
Max Drawdown (10Y) Largest decline over 10 years	-33.80%	—	—
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-4.23%	-4.50%	+0.27%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.90%	1.90%	0.00%

Volatility

PRUIX vs. VFFSX - Volatility Comparison

T. Rowe Price Equity Index 500 Fund - I Class (PRUIX) and Vanguard 500 Index Fund Institutional Select Shares (VFFSX) have volatilities of 2.82% and 2.83%, 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

	PRUIX	VFFSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	2.82%	2.83%	-0.01%
Volatility (6M) Calculated over the trailing 6-month period	8.97%	8.98%	-0.01%
Volatility (1Y) Calculated over the trailing 1-year period	11.86%	11.86%	0.00%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	16.99%	16.90%	+0.09%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.10%	18.41%	-0.31%

PRUIX vs. VFFSX - Expense Ratio Comparison

PRUIX has a 0.05% expense ratio, which is higher than VFFSX's 0.01% 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

PRUIX vs. VFFSX - Dividend Comparison

PRUIX's dividend yield for the trailing twelve months is around 2.21%, more than VFFSX's 1.03% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016
PRUIX T. Rowe Price Equity Index 500 Fund - I Class	2.21%	2.44%	1.28%	1.44%	1.69%	1.64%	2.09%	2.25%	2.77%	1.39%	2.16%
VFFSX Vanguard 500 Index Fund Institutional Select Shares	1.03%	1.14%	1.24%	1.46%	1.70%	1.61%	1.56%	2.15%	2.09%	1.81%	0.00%

Frequently Asked Questions

Can I hold both PRUIX and VFFSX in my portfolio?

With a correlation of 1.00, PRUIX and VFFSX 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, PRUIX or VFFSX?

VFFSX has higher volatility (2.83%) compared to PRUIX (2.82%). In terms of maximum drawdown, PRUIX dropped -33.80% vs VFFSX's -33.82%.

Which has better risk-adjusted returns?

VFFSX currently has the higher Sharpe Ratio (2.52 vs 2.51), 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.