PRBLX vs. THOPX

Last updated Jun 3, 2026

PRBLX (Parnassus Core Equity Fund) and THOPX (Thompson Bond Fund) are both mutual funds - PRBLX is a Large Cap Blend Equities fund managed by Parnassus, while THOPX is a Short-Term Bond fund managed by Thompson IM. Over the past 10 years, PRBLX returned 13.61%/yr vs 4.11%/yr for THOPX. At a 0.05 correlation, their price movements are largely independent. PRBLX charges 0.82%/yr vs 0.71%/yr for THOPX.

Performance

PRBLX vs. THOPX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Parnassus Core Equity Fund (PRBLX) and Thompson Bond Fund (THOPX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, PRBLX achieves a 6.62% return, which is significantly higher than THOPX's 0.95% return. Over the past 10 years, PRBLX has outperformed THOPX with an annualized return of 13.61%, while THOPX has yielded a comparatively lower 4.11% annualized return.

PRBLX

• 1D: 0.42%
• 1M: 3.31%
• YTD: 6.62%
• 6M: 6.14%
• 1Y: 15.71%
• 3Y*: 16.52%
• 5Y*: 10.25%
• 10Y*: 13.61%

THOPX

• 1D: 0.00%
• 1M: 0.09%
• YTD: 0.95%
• 6M: 1.41%
• 1Y: 6.34%
• 3Y*: 8.97%
• 5Y*: 4.05%
• 10Y*: 4.11%

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

PRBLX vs. THOPX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PRBLX Parnassus Core Equity Fund	6.62%	11.67%	18.58%	24.97%	-18.64%	27.59%	21.21%	30.68%	-0.30%	16.63%
THOPX Thompson Bond Fund	0.95%	7.98%	11.54%	6.98%	-7.28%	5.75%	-1.71%	5.56%	1.80%	4.75%

Correlation

The correlation between PRBLX and THOPX is 0.34, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.34
Correlation (3Y) Calculated over the trailing 3-year period	0.22
Correlation (5Y) Calculated over the trailing 5-year period	0.17
Correlation (10Y) Calculated over the trailing 10-year period	0.14
Correlation (All Time) Calculated using the full available price history since Jan 5, 1993	0.05

Over the past year, PRBLX and THOPX have become more correlated (0.34) than their long-term average of 0.05, meaning their price movements have been converging.

Return for Risk

PRBLX vs. THOPX — Risk / Return Rank

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

PRBLX

PRBLX Risk / Return Rank: 19
PRBLX Sharpe Ratio Rank: 21
PRBLX Sortino Ratio Rank: 20
PRBLX Omega Ratio Rank: 20
PRBLX Calmar Ratio Rank: 15
PRBLX Martin Ratio Rank: 20

THOPX

THOPX Risk / Return Rank: 92
THOPX Sharpe Ratio Rank: 95
THOPX Sortino Ratio Rank: 95
THOPX Omega Ratio Rank: 94
THOPX Calmar Ratio Rank: 88
THOPX Martin Ratio Rank: 89

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.

PRBLX vs. THOPX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Parnassus Core Equity Fund (PRBLX) and Thompson Bond Fund (THOPX). 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.

	PRBLX	THOPX	Difference
Sharpe ratio Return per unit of total volatility	1.36	3.35	-1.98
Sortino ratio Return per unit of downside risk	1.95	5.15	-3.20
Omega ratio Gain probability vs. loss probability	1.24	1.76	-0.52
Calmar ratio Return relative to maximum drawdown	1.42	4.34	-2.93
Martin ratio Return relative to average drawdown	5.54	17.74	-12.20
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

PRBLX vs. THOPX - Sharpe Ratio Comparison

The current PRBLX Sharpe Ratio is 1.36, which is lower than the THOPX Sharpe Ratio of 3.35. The chart below compares the historical Sharpe Ratios of PRBLX and THOPX, 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

	PRBLX	THOPX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.36	3.35	-1.98
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.63	1.88	-1.24
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.79	1.87	-1.08
Sharpe Ratio (All Time) Calculated using the full available price history	0.71	1.25	-0.54

Drawdowns

PRBLX vs. THOPX - Drawdown Comparison

The maximum PRBLX drawdown since its inception was -42.20%, which is greater than THOPX's maximum drawdown of -19.45%. Use the drawdown chart below to compare losses from any high point for PRBLX and THOPX.

Drawdown Indicators

	PRBLX	THOPX	Difference
Max Drawdown Largest peak-to-trough decline	-42.20%	-19.45%	-22.75%
Max Drawdown (1Y) Largest decline over 1 year	-11.63%	-1.48%	-10.15%
Max Drawdown (3Y) Largest decline over 3 years	-16.31%	-1.61%	-14.70%
Max Drawdown (5Y) Largest decline over 5 years	-26.31%	-8.00%	-18.31%
Max Drawdown (10Y) Largest decline over 10 years	-30.09%	-11.74%	-18.35%
Current Drawdown Current decline from peak	0.00%	-0.36%	+0.36%
Average Drawdown Average peak-to-trough decline	-4.05%	-1.86%	-2.19%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.97%	0.36%	+2.61%

Volatility

PRBLX vs. THOPX - Volatility Comparison

Parnassus Core Equity Fund (PRBLX) has a higher volatility of 3.07% compared to Thompson Bond Fund (THOPX) at 0.84%. This indicates that PRBLX's price experiences larger fluctuations and is considered to be riskier than THOPX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	PRBLX	THOPX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.07%	0.84%	+2.23%
Volatility (6M) Calculated over the trailing 6-month period	9.12%	1.58%	+7.54%
Volatility (1Y) Calculated over the trailing 1-year period	11.80%	1.91%	+9.89%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	16.25%	2.16%	+14.09%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	17.27%	2.21%	+15.06%

PRBLX vs. THOPX - Expense Ratio Comparison

PRBLX has a 0.82% expense ratio, which is higher than THOPX's 0.71% expense ratio.

Dividends

PRBLX vs. THOPX - Dividend Comparison

PRBLX's dividend yield for the trailing twelve months is around 17.85%, more than THOPX's 5.11% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PRBLX Parnassus Core Equity Fund	17.85%	19.08%	10.00%	6.01%	10.13%	7.77%	5.87%	8.02%	9.64%	7.16%	3.80%	9.62%
THOPX Thompson Bond Fund	5.11%	4.90%	5.34%	5.88%	3.93%	3.59%	5.16%	3.48%	3.07%	3.06%	4.24%	4.58%

Frequently Asked Questions

Can I hold both PRBLX and THOPX in my portfolio?

PRBLX and THOPX have a correlation of 0.34, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, PRBLX or THOPX?

PRBLX has higher volatility (3.07%) compared to THOPX (0.84%). In terms of maximum drawdown, PRBLX dropped -42.20% vs THOPX's -19.45%.

Which has better risk-adjusted returns?

THOPX currently has the higher Sharpe Ratio (3.35 vs 1.36), 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.