WBCIX vs. PRILX

Last updated Jun 24, 2026

WBCIX (William Blair Small-Mid Cap Core Fund) and PRILX (Parnassus Core Equity Institutional Shares) are both mutual funds - WBCIX is a Small Cap Blend Equities fund managed by William Blair, while PRILX is a Large Cap Blend Equities fund managed by Parnassus. Over the past 5 years, WBCIX returned 5.38%/yr vs 10.34%/yr for PRILX. Their correlation of 0.80 suggests significant overlap in exposure. WBCIX charges 1.25%/yr vs 0.61%/yr for PRILX.

Performance

WBCIX vs. PRILX - Performance Comparison

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

Returns By Period

In the year-to-date period, WBCIX achieves a 13.42% return, which is significantly higher than PRILX's 7.08% return.

WBCIX

• 1D: 0.16%
• 1M: 3.74%
• YTD: 13.42%
• 6M: 11.54%
• 1Y: 21.20%
• 3Y*: 11.84%
• 5Y*: 5.38%
• 10Y*: —

PRILX

• 1D: -0.73%
• 1M: 1.76%
• YTD: 7.08%
• 6M: 6.45%
• 1Y: 14.91%
• 3Y*: 16.21%
• 5Y*: 10.34%
• 10Y*: 14.21%

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

WBCIX vs. PRILX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019
WBCIX William Blair Small-Mid Cap Core Fund	13.42%	1.29%	12.04%	13.26%	-17.11%	26.63%	20.60%	10.29%
PRILX Parnassus Core Equity Institutional Shares	7.08%	11.91%	18.81%	25.25%	-18.47%	27.86%	21.50%	7.80%

Correlation

The correlation between WBCIX and PRILX is 0.80, 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	0.80
Correlation (3Y) Calculated over the trailing 3-year period	0.78
Correlation (5Y) Calculated over the trailing 5-year period	0.81
Correlation (All Time) Calculated using the full available price history since Oct 2, 2019	0.80

The correlation between WBCIX and PRILX has been stable across timeframes, ranging from 0.78 to 0.81 - a consistent structural relationship.

Return for Risk

WBCIX vs. PRILX — Risk / Return Rank

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

WBCIX

WBCIX Risk / Return Rank: 28
WBCIX Sharpe Ratio Rank: 25
WBCIX Sortino Ratio Rank: 25
WBCIX Omega Ratio Rank: 23
WBCIX Calmar Ratio Rank: 34
WBCIX Martin Ratio Rank: 34

PRILX

PRILX Risk / Return Rank: 22
PRILX Sharpe Ratio Rank: 24
PRILX Sortino Ratio Rank: 23
PRILX Omega Ratio Rank: 22
PRILX Calmar Ratio Rank: 17
PRILX Martin Ratio Rank: 24

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.

WBCIX vs. PRILX - Risk-Adjusted Trends Comparison

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

	WBCIX	PRILX	Difference
Sharpe ratio: Return per unit of total volatility	1.31	1.29	+0.02
Sortino ratio: Return per unit of downside risk	1.94	1.85	+0.10
Omega ratio: Gain probability vs. loss probability	1.23	1.23	+0.01
Calmar ratio: Return relative to maximum drawdown	2.07	1.38	+0.69
Martin ratio: Return relative to average drawdown	7.19	5.35	+1.84

WBCIX vs. PRILX - Sharpe Ratio Comparison

The current WBCIX Sharpe Ratio is 1.31, which is comparable to the PRILX Sharpe Ratio of 1.29. The chart below compares the historical Sharpe Ratios of WBCIX and PRILX, 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

WBCIX vs. PRILX - Drawdown Comparison

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

Drawdown Indicators

	WBCIX	PRILX	Difference
Max Drawdown Largest peak-to-trough decline	-39.56%	-42.00%	+2.44%
Max Drawdown (1Y) Largest decline over 1 year	-11.06%	-11.61%	+0.55%
Max Drawdown (3Y) Largest decline over 3 years	-23.53%	-16.28%	-7.25%
Max Drawdown (5Y) Largest decline over 5 years	-27.65%	-26.18%	-1.47%
Max Drawdown (10Y) Largest decline over 10 years	—	-30.02%	—
Current Drawdown Current decline from peak	0.00%	-0.86%	+0.86%
Average Drawdown Average peak-to-trough decline	-9.07%	-4.64%	-4.43%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.17%	2.98%	+0.19%

Volatility

WBCIX vs. PRILX - Volatility Comparison

William Blair Small-Mid Cap Core Fund (WBCIX) has a higher volatility of 5.65% compared to Parnassus Core Equity Institutional Shares (PRILX) at 4.61%. This indicates that WBCIX's price experiences larger fluctuations and is considered to be riskier than PRILX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	WBCIX	PRILX	Difference
Volatility (1M) Calculated over the trailing 1-month period	5.65%	4.61%	+1.04%
Volatility (6M) Calculated over the trailing 6-month period	13.17%	9.99%	+3.18%
Volatility (1Y) Calculated over the trailing 1-year period	17.42%	12.37%	+5.05%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	20.77%	16.33%	+4.44%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	23.80%	17.29%	+6.51%

WBCIX vs. PRILX - Expense Ratio Comparison

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

Dividends

WBCIX vs. PRILX - Dividend Comparison

WBCIX's dividend yield for the trailing twelve months is around 2.63%, less than PRILX's 17.86% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PRILX Parnassus Core Equity Institutional Shares	17.86%	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	2.63%	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 WBCIX and PRILX in my portfolio?

WBCIX and PRILX have a correlation of 0.80, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, WBCIX or PRILX?

WBCIX has higher volatility (5.65%) compared to PRILX (4.61%). In terms of maximum drawdown, WBCIX dropped -39.56% vs PRILX's -42.00%.

Which has better risk-adjusted returns?

WBCIX currently has the higher Sharpe Ratio (1.31 vs 1.29), 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.