PRILX vs. WBCIX

Last updated Jun 3, 2026

PRILX (Parnassus Core Equity Institutional Shares) and WBCIX (William Blair Small-Mid Cap Core Fund) are both mutual funds - PRILX is a Large Cap Blend Equities fund managed by Parnassus, while WBCIX is a Small Cap Blend Equities fund managed by William Blair. Over the past 5 years, PRILX returned 10.48%/yr vs 4.93%/yr for WBCIX. Their correlation of 0.80 suggests significant overlap in exposure. PRILX charges 0.61%/yr vs 1.25%/yr for WBCIX.

Performance

PRILX vs. WBCIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Parnassus Core Equity Institutional Shares (PRILX) and William Blair Small-Mid Cap Core Fund (WBCIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, PRILX achieves a 6.70% return, which is significantly lower than WBCIX's 10.77% return.

PRILX

• 1D: 0.44%
• 1M: 3.31%
• YTD: 6.70%
• 6M: 6.25%
• 1Y: 15.94%
• 3Y*: 16.76%
• 5Y*: 10.48%
• 10Y*: 13.85%

WBCIX

• 1D: -0.05%
• 1M: 3.60%
• YTD: 10.77%
• 6M: 11.35%
• 1Y: 20.86%
• 3Y*: 10.93%
• 5Y*: 4.93%
• 10Y*: —

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

PRILX vs. WBCIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019
PRILX Parnassus Core Equity Institutional Shares	6.70%	11.91%	18.81%	25.25%	-18.47%	27.86%	21.50%	9.54%
WBCIX William Blair Small-Mid Cap Core Fund	10.77%	1.29%	12.04%	13.26%	-17.11%	26.63%	20.60%	10.29%

Correlation

The correlation between PRILX and WBCIX is 0.79, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.79
Correlation (3Y) Calculated over the trailing 3-year period	0.77
Correlation (5Y) Calculated over the trailing 5-year period	0.80
Correlation (All Time) Calculated using the full available price history since Oct 3, 2019	0.80

The correlation between PRILX and WBCIX has been stable across timeframes, ranging from 0.77 to 0.80 - a consistent structural relationship.

Return for Risk

PRILX vs. WBCIX — Risk / Return Rank

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

PRILX

PRILX Risk / Return Rank: 20
PRILX Sharpe Ratio Rank: 22
PRILX Sortino Ratio Rank: 21
PRILX Omega Ratio Rank: 20
PRILX Calmar Ratio Rank: 15
PRILX Martin Ratio Rank: 20

WBCIX

WBCIX Risk / Return Rank: 20
WBCIX Sharpe Ratio Rank: 18
WBCIX Sortino Ratio Rank: 18
WBCIX Omega Ratio Rank: 17
WBCIX Calmar Ratio Rank: 23
WBCIX Martin Ratio Rank: 26

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. WBCIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Parnassus Core Equity Institutional Shares (PRILX) and William Blair Small-Mid Cap Core Fund (WBCIX). 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.

	PRILX	WBCIX	Difference
Sharpe ratio Return per unit of total volatility	1.39	1.24	+0.15
Sortino ratio Return per unit of downside risk	1.98	1.86	+0.13
Omega ratio Gain probability vs. loss probability	1.24	1.22	+0.02
Calmar ratio Return relative to maximum drawdown	1.44	1.84	-0.40
Martin ratio Return relative to average drawdown	5.64	6.44	-0.80
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

PRILX vs. WBCIX - Sharpe Ratio Comparison

The current PRILX Sharpe Ratio is 1.39, which is comparable to the WBCIX Sharpe Ratio of 1.24. The chart below compares the historical Sharpe Ratios of PRILX and WBCIX, 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

	PRILX	WBCIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.39	1.24	+0.15
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.65	0.24	+0.41
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.81	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.66	0.46	+0.21

Drawdowns

PRILX vs. WBCIX - Drawdown Comparison

The maximum PRILX drawdown since its inception was -42.00%, which is greater than WBCIX's maximum drawdown of -39.56%. Use the drawdown chart below to compare losses from any high point for PRILX and WBCIX.

Drawdown Indicators

	PRILX	WBCIX	Difference
Max Drawdown Largest peak-to-trough decline	-42.00%	-39.56%	-2.44%
Max Drawdown (1Y) Largest decline over 1 year	-11.61%	-11.06%	-0.55%
Max Drawdown (3Y) Largest decline over 3 years	-16.28%	-23.53%	+7.25%
Max Drawdown (5Y) Largest decline over 5 years	-26.18%	-27.65%	+1.47%
Max Drawdown (10Y) Largest decline over 10 years	-30.02%	—	—
Current Drawdown Current decline from peak	0.00%	-0.38%	+0.38%
Average Drawdown Average peak-to-trough decline	-4.65%	-9.14%	+4.49%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.96%	3.15%	-0.19%

Volatility

PRILX vs. WBCIX - Volatility Comparison

The current volatility for Parnassus Core Equity Institutional Shares (PRILX) is 3.07%, while William Blair Small-Mid Cap Core Fund (WBCIX) has a volatility of 4.91%. This indicates that PRILX experiences smaller price fluctuations and is considered to be less risky than WBCIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	PRILX	WBCIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.07%	4.91%	-1.84%
Volatility (6M) Calculated over the trailing 6-month period	9.10%	12.47%	-3.37%
Volatility (1Y) Calculated over the trailing 1-year period	11.78%	16.84%	-5.06%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	16.24%	20.69%	-4.45%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	17.25%	23.82%	-6.57%

PRILX vs. WBCIX - Expense Ratio Comparison

PRILX has a 0.61% expense ratio, which is lower than WBCIX's 1.25% expense ratio.

Dividends

PRILX vs. WBCIX - Dividend Comparison

PRILX's dividend yield for the trailing twelve months is around 17.92%, more than WBCIX's 2.69% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PRILX Parnassus Core Equity Institutional Shares	17.92%	19.16%	10.17%	6.18%	10.34%	7.94%	6.04%	8.23%	9.89%	7.37%	3.99%	9.84%
WBCIX William Blair Small-Mid Cap Core Fund	2.69%	2.98%	1.35%	0.15%	0.00%	0.00%	0.00%	0.06%	0.00%	0.00%	0.00%	0.00%

Frequently Asked Questions

Can I hold both PRILX and WBCIX in my portfolio?

PRILX and WBCIX have a correlation of 0.79, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, PRILX or WBCIX?

WBCIX has higher volatility (4.91%) compared to PRILX (3.07%). In terms of maximum drawdown, PRILX dropped -42.00% vs WBCIX's -39.56%.

Which has better risk-adjusted returns?

PRILX currently has the higher Sharpe Ratio (1.39 vs 1.24), 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.