PIODX vs. VFFSX

Last updated Jun 5, 2026

PIODX (Pioneer Fund) and VFFSX (Vanguard 500 Index Fund Institutional Select Shares) are both Large Cap Blend Equities funds. Over the past 5 years, PIODX returned 14.08%/yr vs 13.90%/yr for VFFSX. With a 0.96 correlation, they move nearly in lockstep. PIODX charges 1.06%/yr vs 0.01%/yr for VFFSX.

Performance

PIODX vs. VFFSX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Pioneer Fund (PIODX) and Vanguard 500 Index Fund Institutional Select Shares (VFFSX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, PIODX achieves a 12.16% return, which is significantly higher than VFFSX's 10.88% return.

PIODX

• 1D: -1.04%
• 1M: 1.29%
• YTD: 12.16%
• 6M: 11.60%
• 1Y: 33.20%
• 3Y*: 25.61%
• 5Y*: 14.08%
• 10Y*: 16.62%

VFFSX

• 1D: -0.74%
• 1M: 4.17%
• YTD: 10.88%
• 6M: 10.79%
• 1Y: 28.02%
• 3Y*: 22.45%
• 5Y*: 13.90%
• 10Y*: —

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

PIODX vs. VFFSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PIODX Pioneer Fund	12.16%	23.30%	22.62%	28.45%	-19.43%	27.40%	24.01%	31.04%	-1.48%	20.92%
VFFSX Vanguard 500 Index Fund Institutional Select Shares	10.88%	17.87%	25.00%	26.28%	-18.14%	29.24%	18.35%	31.88%	-4.42%	20.80%

Correlation

The correlation between PIODX and VFFSX is 0.93, indicating a strong positive relationship between their price movements. Combining them offers limited diversification - they tend to fall together during downturns.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.93
Correlation (3Y) Calculated over the trailing 3-year period	0.94
Correlation (5Y) Calculated over the trailing 5-year period	0.96
Correlation (All Time) Calculated using the full available price history since Jan 4, 2017	0.96

The correlation between PIODX and VFFSX has been stable across timeframes, ranging from 0.93 to 0.96 - a consistent structural relationship.

Return for Risk

PIODX vs. VFFSX — Risk / Return Rank

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

PIODX

PIODX Risk / Return Rank: 62
PIODX Sharpe Ratio Rank: 57
PIODX Sortino Ratio Rank: 51
PIODX Omega Ratio Rank: 49
PIODX Calmar Ratio Rank: 75
PIODX Martin Ratio Rank: 78

VFFSX

VFFSX Risk / Return Rank: 66
VFFSX Sharpe Ratio Rank: 64
VFFSX Sortino Ratio Rank: 59
VFFSX Omega Ratio Rank: 60
VFFSX Calmar Ratio Rank: 67
VFFSX Martin Ratio Rank: 79

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.

PIODX vs. VFFSX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Pioneer Fund (PIODX) 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.

	PIODX	VFFSX	Difference
Sharpe ratio: Return per unit of total volatility	2.23	2.37	-0.14
Sortino ratio: Return per unit of downside risk	3.01	3.24	-0.23
Omega ratio: Gain probability vs. loss probability	1.38	1.43	-0.05
Calmar ratio: Return relative to maximum drawdown	3.36	3.17	+0.20
Martin ratio: Return relative to average drawdown	14.64	14.79	-0.15
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

PIODX vs. VFFSX - Sharpe Ratio Comparison

The current PIODX Sharpe Ratio is 2.23, which is comparable to the VFFSX Sharpe Ratio of 2.37. The chart below compares the historical Sharpe Ratios of PIODX 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

	PIODX	VFFSX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.23	2.37	-0.14
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.74	0.83	-0.09
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.88	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.53	0.85	-0.32

Drawdowns

PIODX vs. VFFSX - Drawdown Comparison

The maximum PIODX drawdown since its inception was -53.40%, which is greater than VFFSX's maximum drawdown of -33.82%. Use the drawdown chart below to compare losses from any high point for PIODX and VFFSX.

Drawdown Indicators

	PIODX	VFFSX	Difference
Max Drawdown Largest peak-to-trough decline	-53.40%	-33.82%	-19.58%
Max Drawdown (1Y) Largest decline over 1 year	-9.99%	-8.90%	-1.09%
Max Drawdown (3Y) Largest decline over 3 years	-21.52%	-18.75%	-2.77%
Max Drawdown (5Y) Largest decline over 5 years	-26.55%	-24.51%	-2.04%
Max Drawdown (10Y) Largest decline over 10 years	-30.14%	—	—
Current Drawdown Current decline from peak	-1.04%	-0.74%	-0.30%
Average Drawdown Average peak-to-trough decline	-8.60%	-4.50%	-4.10%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.29%	1.90%	+0.39%

Volatility

PIODX vs. VFFSX - Volatility Comparison

Pioneer Fund (PIODX) has a higher volatility of 3.89% compared to Vanguard 500 Index Fund Institutional Select Shares (VFFSX) at 2.93%. This indicates that PIODX's price experiences larger fluctuations and is considered to be riskier than VFFSX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	PIODX	VFFSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.89%	2.93%	+0.96%
Volatility (6M) Calculated over the trailing 6-month period	11.31%	9.00%	+2.31%
Volatility (1Y) Calculated over the trailing 1-year period	15.09%	11.89%	+3.20%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	19.16%	16.90%	+2.26%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.86%	18.41%	+0.45%

PIODX vs. VFFSX - Expense Ratio Comparison

PIODX has a 1.06% expense ratio, which is higher than VFFSX's 0.01% expense ratio.

Dividends

PIODX vs. VFFSX - Dividend Comparison

PIODX's dividend yield for the trailing twelve months is around 8.94%, more than VFFSX's 1.04% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PIODX Pioneer Fund	8.94%	10.04%	14.17%	2.86%	4.13%	16.18%	5.82%	9.37%	15.37%	21.35%	20.51%	14.53%
VFFSX Vanguard 500 Index Fund Institutional Select Shares	1.04%	1.14%	1.24%	1.46%	1.70%	1.61%	1.56%	2.15%	2.09%	1.81%	0.00%	0.00%

Frequently Asked Questions

Can I hold both PIODX and VFFSX in my portfolio?

With a correlation of 0.93, PIODX 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, PIODX or VFFSX?

PIODX has higher volatility (3.89%) compared to VFFSX (2.93%). In terms of maximum drawdown, PIODX dropped -53.40% vs VFFSX's -33.82%.

Which has better risk-adjusted returns?

VFFSX currently has the higher Sharpe Ratio (2.37 vs 2.23), 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.