OSTFX vs. VFFSX

Last updated Jun 24, 2026

OSTFX (Osterweis Fund) and VFFSX (Vanguard 500 Index Fund Institutional Select Shares) are both Large Cap Blend Equities funds. Over the past 5 years, OSTFX returned 7.20%/yr vs 13.60%/yr for VFFSX. Their correlation of 0.94 suggests significant overlap in exposure. OSTFX charges 0.95%/yr vs 0.01%/yr for VFFSX.

Performance

OSTFX vs. VFFSX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Osterweis Fund (OSTFX) 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, OSTFX achieves a 4.18% return, which is significantly lower than VFFSX's 9.79% return.

OSTFX

• 1D: -0.67%
• 1M: -0.53%
• YTD: 4.18%
• 6M: 3.29%
• 1Y: 15.34%
• 3Y*: 14.30%
• 5Y*: 7.20%
• 10Y*: 12.08%

VFFSX

• 1D: -0.36%
• 1M: 0.10%
• YTD: 9.79%
• 6M: 8.79%
• 1Y: 25.51%
• 3Y*: 21.39%
• 5Y*: 13.60%
• 10Y*: —

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

OSTFX vs. VFFSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
OSTFX Osterweis Fund	4.18%	12.85%	13.48%	22.64%	-22.01%	22.58%	23.20%	43.39%	-7.85%	14.82%
VFFSX Vanguard 500 Index Fund Institutional Select Shares	9.79%	17.87%	25.00%	26.28%	-18.14%	29.24%	18.35%	31.88%	-4.42%	20.80%

Correlation

The correlation between OSTFX and VFFSX is 0.90, 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	0.90
Correlation (3Y) Calculated over the trailing 3-year period	0.92
Correlation (5Y) Calculated over the trailing 5-year period	0.95
Correlation (All Time) Calculated using the full available price history since Jan 3, 2017	0.94

The correlation between OSTFX and VFFSX has been stable across timeframes, ranging from 0.90 to 0.95 - a consistent structural relationship.

Return for Risk

OSTFX vs. VFFSX — Risk / Return Rank

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

OSTFX

OSTFX Risk / Return Rank: 28
OSTFX Sharpe Ratio Rank: 28
OSTFX Sortino Ratio Rank: 28
OSTFX Omega Ratio Rank: 26
OSTFX Calmar Ratio Rank: 23
OSTFX Martin Ratio Rank: 33

VFFSX

VFFSX Risk / Return Rank: 65
VFFSX Sharpe Ratio Rank: 64
VFFSX Sortino Ratio Rank: 57
VFFSX Omega Ratio Rank: 59
VFFSX Calmar Ratio Rank: 68
VFFSX Martin Ratio Rank: 78

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.

OSTFX vs. VFFSX - Risk-Adjusted Trends Comparison

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

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.

	OSTFX	VFFSX	Difference
Sharpe ratio: Return per unit of total volatility	1.39	2.15	-0.76
Sortino ratio: Return per unit of downside risk	2.03	2.91	-0.88
Omega ratio: Gain probability vs. loss probability	1.24	1.39	-0.15
Calmar ratio: Return relative to maximum drawdown	1.63	3.02	-1.39
Martin ratio: Return relative to average drawdown	7.08	13.62	-6.54

OSTFX vs. VFFSX - Sharpe Ratio Comparison

The current OSTFX Sharpe Ratio is 1.39, which is lower than the VFFSX Sharpe Ratio of 2.15. The chart below compares the historical Sharpe Ratios of OSTFX 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.

Drawdowns

OSTFX vs. VFFSX - Drawdown Comparison

The maximum OSTFX drawdown since its inception was -40.63%, which is greater than VFFSX's maximum drawdown of -33.82%. Use the drawdown chart below to compare losses from any high point for OSTFX and VFFSX.

Drawdown Indicators

	OSTFX	VFFSX	Difference
Max Drawdown Largest peak-to-trough decline	-40.63%	-33.82%	-6.81%
Max Drawdown (1Y) Largest decline over 1 year	-10.06%	-8.90%	-1.16%
Max Drawdown (3Y) Largest decline over 3 years	-15.80%	-18.75%	+2.95%
Max Drawdown (5Y) Largest decline over 5 years	-27.62%	-24.51%	-3.11%
Max Drawdown (10Y) Largest decline over 10 years	-32.54%	—	—
Current Drawdown Current decline from peak	-1.52%	-1.72%	+0.20%
Average Drawdown Average peak-to-trough decline	-6.83%	-4.49%	-2.34%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.31%	1.97%	+0.34%

Volatility

OSTFX vs. VFFSX - Volatility Comparison

The current volatility for Osterweis Fund (OSTFX) is 3.53%, while Vanguard 500 Index Fund Institutional Select Shares (VFFSX) has a volatility of 4.67%. This indicates that OSTFX experiences smaller price fluctuations and is considered to be less risky than VFFSX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	OSTFX	VFFSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.53%	4.67%	-1.14%
Volatility (6M) Calculated over the trailing 6-month period	9.18%	9.84%	-0.66%
Volatility (1Y) Calculated over the trailing 1-year period	11.83%	12.50%	-0.67%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	15.67%	16.99%	-1.32%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	16.84%	18.42%	-1.58%

OSTFX vs. VFFSX - Expense Ratio Comparison

OSTFX has a 0.95% expense ratio, which is higher than VFFSX's 0.01% expense ratio.

Dividends

OSTFX vs. VFFSX - Dividend Comparison

OSTFX's dividend yield for the trailing twelve months is around 5.74%, more than VFFSX's 1.05% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
OSTFX Osterweis Fund	5.74%	5.98%	14.93%	4.01%	7.81%	12.83%	5.48%	14.46%	29.80%	43.97%	7.35%	22.55%
VFFSX Vanguard 500 Index Fund Institutional Select Shares	1.05%	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 OSTFX and VFFSX in my portfolio?

OSTFX and VFFSX have a correlation of 0.90, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, OSTFX or VFFSX?

VFFSX has higher volatility (4.67%) compared to OSTFX (3.53%). In terms of maximum drawdown, OSTFX dropped -40.63% vs VFFSX's -33.82%.

Which has better risk-adjusted returns?

VFFSX currently has the higher Sharpe Ratio (2.15 vs 1.39), 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.