PRILX vs. FXAIX

Last updated Jun 25, 2026

PRILX (Parnassus Core Equity Institutional Shares) and FXAIX (Fidelity 500 Index Fund) are both mutual funds - PRILX is a Large Cap Blend Equities fund managed by Parnassus, while FXAIX is a S&P 500 fund tracking the S&P 500 Index. Over the past 10 years, PRILX returned 14.05%/yr vs 15.63%/yr for FXAIX. With a 0.95 correlation, they move nearly in lockstep. PRILX charges 0.61%/yr vs 0.02%/yr for FXAIX.

Performance

PRILX vs. FXAIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Parnassus Core Equity Institutional Shares (PRILX) and Fidelity 500 Index Fund (FXAIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, PRILX achieves a 5.53% return, which is significantly lower than FXAIX's 8.21% return. Over the past 10 years, PRILX has underperformed FXAIX with an annualized return of 14.05%, while FXAIX has yielded a comparatively higher 15.63% annualized return.

PRILX

• 1D: -1.45%
• 1M: 0.29%
• YTD: 5.53%
• 6M: 4.60%
• 1Y: 11.90%
• 3Y*: 15.65%
• 5Y*: 9.90%
• 10Y*: 14.05%

FXAIX

• 1D: -1.43%
• 1M: -1.34%
• YTD: 8.21%
• 6M: 6.88%
• 1Y: 22.35%
• 3Y*: 20.81%
• 5Y*: 13.14%
• 10Y*: 15.63%

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

PRILX vs. FXAIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PRILX Parnassus Core Equity Institutional Shares	5.53%	11.91%	18.81%	25.25%	-18.47%	27.86%	21.50%	30.95%	-0.06%	16.87%
FXAIX Fidelity 500 Index Fund	8.21%	17.84%	25.01%	26.29%	-18.14%	28.71%	18.42%	31.48%	-4.43%	21.82%

Correlation

The correlation between PRILX and FXAIX 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	0.95
Correlation (10Y) Calculated over the trailing 10-year period	0.95
Correlation (All Time) Calculated using the full available price history since May 4, 2011	0.95

The correlation between PRILX and FXAIX has been stable across timeframes, ranging from 0.93 to 0.95 - a consistent structural relationship.

Return for Risk

PRILX vs. FXAIX — Risk / Return Rank

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

PRILX

PRILX Risk / Return Rank: 17
PRILX Sharpe Ratio Rank: 18
PRILX Sortino Ratio Rank: 17
PRILX Omega Ratio Rank: 16
PRILX Calmar Ratio Rank: 14
PRILX Martin Ratio Rank: 19

FXAIX

FXAIX Risk / Return Rank: 52
FXAIX Sharpe Ratio Rank: 49
FXAIX Sortino Ratio Rank: 44
FXAIX Omega Ratio Rank: 47
FXAIX Calmar Ratio Rank: 53
FXAIX Martin Ratio Rank: 66

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.

PRILX vs. FXAIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Parnassus Core Equity Institutional Shares (PRILX) and Fidelity 500 Index Fund (FXAIX). 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.

	PRILX	FXAIX	Difference
Sharpe ratio: Return per unit of total volatility	1.08	1.90	-0.82
Sortino ratio: Return per unit of downside risk	1.56	2.59	-1.03
Omega ratio: Gain probability vs. loss probability	1.19	1.34	-0.15
Calmar ratio: Return relative to maximum drawdown	1.15	2.68	-1.53
Martin ratio: Return relative to average drawdown	4.47	12.03	-7.56

PRILX vs. FXAIX - Sharpe Ratio Comparison

The current PRILX Sharpe Ratio is 1.08, which is lower than the FXAIX Sharpe Ratio of 1.90. The chart below compares the historical Sharpe Ratios of PRILX and FXAIX, 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

PRILX vs. FXAIX - Drawdown Comparison

The maximum PRILX drawdown since its inception was -42.00%, which is greater than FXAIX's maximum drawdown of -33.79%. Use the drawdown chart below to compare losses from any high point for PRILX and FXAIX.

Drawdown Indicators

	PRILX	FXAIX	Difference
Max Drawdown Largest peak-to-trough decline	-42.00%	-33.79%	-8.21%
Max Drawdown (1Y) Largest decline over 1 year	-11.61%	-8.89%	-2.72%
Max Drawdown (3Y) Largest decline over 3 years	-16.28%	-18.76%	+2.48%
Max Drawdown (5Y) Largest decline over 5 years	-26.18%	-24.50%	-1.68%
Max Drawdown (10Y) Largest decline over 10 years	-30.02%	-33.79%	+3.77%
Current Drawdown Current decline from peak	-2.29%	-3.13%	+0.84%
Average Drawdown Average peak-to-trough decline	-4.64%	-3.79%	-0.85%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.98%	1.98%	+1.00%

Volatility

PRILX vs. FXAIX - Volatility Comparison

Parnassus Core Equity Institutional Shares (PRILX) and Fidelity 500 Index Fund (FXAIX) have volatilities of 4.86% and 4.90%, 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

	PRILX	FXAIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.86%	4.90%	-0.04%
Volatility (6M) Calculated over the trailing 6-month period	10.06%	9.93%	+0.13%
Volatility (1Y) Calculated over the trailing 1-year period	12.44%	12.57%	-0.13%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	16.35%	17.02%	-0.67%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	17.26%	18.09%	-0.83%

PRILX vs. FXAIX - Expense Ratio Comparison

PRILX has a 0.61% expense ratio, which is higher than FXAIX's 0.02% expense ratio.

Dividends

PRILX vs. FXAIX - Dividend Comparison

PRILX's dividend yield for the trailing twelve months is around 18.12%, more than FXAIX's 1.06% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FXAIX Fidelity 500 Index Fund	1.06%	1.11%	1.25%	1.45%	1.69%	1.22%	1.60%	2.06%	2.72%	1.97%	2.52%	2.83%
PRILX Parnassus Core Equity Institutional Shares	18.12%	19.16%	10.17%	6.18%	10.34%	7.94%	6.04%	8.23%	9.89%	7.37%	3.99%	9.84%

Frequently Asked Questions

Can I hold both PRILX and FXAIX in my portfolio?

With a correlation of 0.93, PRILX and FXAIX 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, PRILX or FXAIX?

FXAIX has higher volatility (4.90%) compared to PRILX (4.86%). In terms of maximum drawdown, PRILX dropped -42.00% vs FXAIX's -33.79%.

Which has better risk-adjusted returns?

FXAIX currently has the higher Sharpe Ratio (1.90 vs 1.08), 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.