WMFFX vs. BUFBX

Last updated Jun 4, 2026

WMFFX (Washington Mutual Investors Fund Class F-2) and BUFBX (Buffalo Flexible Income Fund) are both Large Cap Value Equities funds. Over the past 10 years, WMFFX returned 13.00%/yr vs 10.00%/yr for BUFBX. Their correlation of 0.87 suggests significant overlap in exposure. WMFFX charges 0.37%/yr vs 1.01%/yr for BUFBX.

Performance

WMFFX vs. BUFBX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Washington Mutual Investors Fund Class F-2 (WMFFX) and Buffalo Flexible Income Fund (BUFBX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, WMFFX achieves a 5.96% return, which is significantly lower than BUFBX's 12.83% return. Over the past 10 years, WMFFX has outperformed BUFBX with an annualized return of 13.00%, while BUFBX has yielded a comparatively lower 10.00% annualized return.

WMFFX

• 1D: 0.39%
• 1M: 2.81%
• YTD: 5.96%
• 6M: 6.10%
• 1Y: 17.77%
• 3Y*: 18.31%
• 5Y*: 12.04%
• 10Y*: 13.00%

BUFBX

• 1D: 0.57%
• 1M: 3.64%
• YTD: 12.83%
• 6M: 12.77%
• 1Y: 19.88%
• 3Y*: 13.91%
• 5Y*: 11.23%
• 10Y*: 10.00%

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

WMFFX vs. BUFBX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
WMFFX Washington Mutual Investors Fund Class F-2	5.96%	17.42%	19.24%	16.96%	-8.27%	28.71%	7.89%	25.03%	-5.98%	20.23%
BUFBX Buffalo Flexible Income Fund	12.83%	10.37%	10.26%	7.42%	3.97%	29.97%	-2.27%	18.76%	-7.01%	13.20%

Correlation

The correlation between WMFFX and BUFBX is 0.50, 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	0.50
Correlation (3Y) Calculated over the trailing 3-year period	0.68
Correlation (5Y) Calculated over the trailing 5-year period	0.80
Correlation (10Y) Calculated over the trailing 10-year period	0.84
Correlation (All Time) Calculated using the full available price history since Aug 4, 2008	0.87

Over the past year, the correlation between WMFFX and BUFBX has dropped to 0.50 - well below their long-term average of 0.87, suggesting their price drivers have been diverging.

Return for Risk

WMFFX vs. BUFBX — Risk / Return Rank

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

WMFFX

WMFFX Risk / Return Rank: 39
WMFFX Sharpe Ratio Rank: 39
WMFFX Sortino Ratio Rank: 37
WMFFX Omega Ratio Rank: 38
WMFFX Calmar Ratio Rank: 34
WMFFX Martin Ratio Rank: 46

BUFBX

BUFBX Risk / Return Rank: 71
BUFBX Sharpe Ratio Rank: 60
BUFBX Sortino Ratio Rank: 59
BUFBX Omega Ratio Rank: 52
BUFBX Calmar Ratio Rank: 97
BUFBX 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.

WMFFX vs. BUFBX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Washington Mutual Investors Fund Class F-2 (WMFFX) and Buffalo Flexible Income Fund (BUFBX). 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.

	WMFFX	BUFBX	Difference
Sharpe ratio: Return per unit of total volatility	1.80	2.28	-0.48
Sortino ratio: Return per unit of downside risk	2.56	3.24	-0.68
Omega ratio: Gain probability vs. loss probability	1.33	1.40	-0.07
Calmar ratio: Return relative to maximum drawdown	2.21	7.18	-4.96
Martin ratio: Return relative to average drawdown	9.58	17.54	-7.95
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

WMFFX vs. BUFBX - Sharpe Ratio Comparison

The current WMFFX Sharpe Ratio is 1.80, which is comparable to the BUFBX Sharpe Ratio of 2.28. The chart below compares the historical Sharpe Ratios of WMFFX and BUFBX, 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

	WMFFX	BUFBX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.80	2.28	-0.48
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.86	0.84	+0.02
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.80	0.64	+0.16
Sharpe Ratio (All Time) Calculated using the full available price history	0.60	0.59	+0.01

Drawdowns

WMFFX vs. BUFBX - Drawdown Comparison

The maximum WMFFX drawdown since its inception was -47.21%, which is greater than BUFBX's maximum drawdown of -39.78%. Use the drawdown chart below to compare losses from any high point for WMFFX and BUFBX.

Drawdown Indicators

	WMFFX	BUFBX	Difference
Max Drawdown Largest peak-to-trough decline	-47.21%	-39.78%	-7.43%
Max Drawdown (1Y) Largest decline over 1 year	-8.36%	-2.83%	-5.53%
Max Drawdown (3Y) Largest decline over 3 years	-14.64%	-12.85%	-1.79%
Max Drawdown (5Y) Largest decline over 5 years	-18.53%	-14.67%	-3.86%
Max Drawdown (10Y) Largest decline over 10 years	-34.63%	-35.51%	+0.88%
Current Drawdown Current decline from peak	0.00%	-0.22%	+0.22%
Average Drawdown Average peak-to-trough decline	-5.36%	-4.72%	-0.64%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.93%	1.16%	+0.77%

Volatility

WMFFX vs. BUFBX - Volatility Comparison

The current volatility for Washington Mutual Investors Fund Class F-2 (WMFFX) is 2.42%, while Buffalo Flexible Income Fund (BUFBX) has a volatility of 3.06%. This indicates that WMFFX experiences smaller price fluctuations and is considered to be less risky than BUFBX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	WMFFX	BUFBX	Difference
Volatility (1M) Calculated over the trailing 1-month period	2.42%	3.06%	-0.64%
Volatility (6M) Calculated over the trailing 6-month period	7.89%	6.61%	+1.28%
Volatility (1Y) Calculated over the trailing 1-year period	10.32%	8.93%	+1.39%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	14.11%	13.40%	+0.71%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	16.33%	15.60%	+0.73%

WMFFX vs. BUFBX - Expense Ratio Comparison

WMFFX has a 0.37% expense ratio, which is lower than BUFBX's 1.01% expense ratio.

Dividends

WMFFX vs. BUFBX - Dividend Comparison

WMFFX's dividend yield for the trailing twelve months is around 9.74%, more than BUFBX's 7.99% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
BUFBX Buffalo Flexible Income Fund	7.99%	9.10%	3.77%	3.48%	4.16%	5.57%	3.33%	2.73%	6.01%	5.49%	2.39%	3.67%
WMFFX Washington Mutual Investors Fund Class F-2	9.74%	10.28%	10.27%	5.92%	6.53%	6.24%	3.26%	6.33%	4.59%	7.43%	6.56%	6.44%

Frequently Asked Questions

Can I hold both WMFFX and BUFBX in my portfolio?

WMFFX and BUFBX have a correlation of 0.50, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, WMFFX or BUFBX?

BUFBX has higher volatility (3.06%) compared to WMFFX (2.42%). In terms of maximum drawdown, WMFFX dropped -47.21% vs BUFBX's -39.78%.

Which has better risk-adjusted returns?

BUFBX currently has the higher Sharpe Ratio (2.28 vs 1.80), 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.