BUFTX vs. NEEGX

Last updated Jun 5, 2026

BUFTX (Buffalo Discovery Fund) and NEEGX (Needham Growth Fund) are both Mid Cap Growth Equities funds. Over the past 10 years, BUFTX returned 7.57%/yr vs 16.36%/yr for NEEGX. Their correlation of 0.87 suggests significant overlap in exposure. BUFTX charges 1.00%/yr vs 1.78%/yr for NEEGX.

Performance

BUFTX vs. NEEGX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Buffalo Discovery Fund (BUFTX) and Needham Growth Fund (NEEGX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, BUFTX achieves a -3.41% return, which is significantly lower than NEEGX's 59.15% return. Over the past 10 years, BUFTX has underperformed NEEGX with an annualized return of 7.57%, while NEEGX has yielded a comparatively higher 16.36% annualized return.

BUFTX

• 1D: -1.25%
• 1M: 1.34%
• YTD: -3.41%
• 6M: -4.97%
• 1Y: -7.07%
• 3Y*: 3.88%
• 5Y*: -1.10%
• 10Y*: 7.57%

NEEGX

• 1D: -0.12%
• 1M: 14.40%
• YTD: 59.15%
• 6M: 55.64%
• 1Y: 95.16%
• 3Y*: 28.67%
• 5Y*: 14.57%
• 10Y*: 16.36%

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

BUFTX vs. NEEGX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
BUFTX Buffalo Discovery Fund	-3.41%	-1.83%	5.31%	24.30%	-28.78%	11.55%	33.90%	31.62%	-6.52%	25.43%
NEEGX Needham Growth Fund	59.15%	8.76%	14.45%	26.85%	-33.57%	27.63%	41.73%	42.33%	-10.56%	8.33%

Correlation

The correlation between BUFTX and NEEGX is 0.69, 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	0.69
Correlation (3Y) Calculated over the trailing 3-year period	0.76
Correlation (5Y) Calculated over the trailing 5-year period	0.83
Correlation (10Y) Calculated over the trailing 10-year period	0.84
Correlation (All Time) Calculated using the full available price history since Apr 17, 2001	0.87

The correlation between BUFTX and NEEGX shifts across timeframes, from 0.69 (1 year) to 0.87 (all time), reflecting how their relationship changes across market environments.

Return for Risk

BUFTX vs. NEEGX — Risk / Return Rank

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

BUFTX

BUFTX Risk / Return Rank: 1
BUFTX Sharpe Ratio Rank: 1
BUFTX Sortino Ratio Rank: 1
BUFTX Omega Ratio Rank: 1
BUFTX Calmar Ratio Rank: 1
BUFTX Martin Ratio Rank: 1

NEEGX

NEEGX Risk / Return Rank: 92
NEEGX Sharpe Ratio Rank: 97
NEEGX Sortino Ratio Rank: 86
NEEGX Omega Ratio Rank: 81
NEEGX Calmar Ratio Rank: 97
NEEGX Martin Ratio Rank: 96

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.

BUFTX vs. NEEGX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Buffalo Discovery Fund (BUFTX) and Needham Growth Fund (NEEGX). 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.

	BUFTX	NEEGX	Difference
Sharpe ratio: Return per unit of total volatility	-0.42	3.61	-4.03
Sortino ratio: Return per unit of downside risk	-0.49	4.17	-4.66
Omega ratio: Gain probability vs. loss probability	0.94	1.54	-0.60
Calmar ratio: Return relative to maximum drawdown	-0.34	7.36	-7.70
Martin ratio: Return relative to average drawdown	-0.79	25.03	-25.81
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

BUFTX vs. NEEGX - Sharpe Ratio Comparison

The current BUFTX Sharpe Ratio is -0.42, which is lower than the NEEGX Sharpe Ratio of 3.61. The chart below compares the historical Sharpe Ratios of BUFTX and NEEGX, 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

	BUFTX	NEEGX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	-0.42	3.61	-4.03
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	-0.05	0.52	-0.57
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.37	0.65	-0.28
Sharpe Ratio (All Time) Calculated using the full available price history	0.36	0.59	-0.23

Drawdowns

BUFTX vs. NEEGX - Drawdown Comparison

The maximum BUFTX drawdown since its inception was -60.45%, which is greater than NEEGX's maximum drawdown of -53.60%. Use the drawdown chart below to compare losses from any high point for BUFTX and NEEGX.

Drawdown Indicators

	BUFTX	NEEGX	Difference
Max Drawdown Largest peak-to-trough decline	-60.45%	-53.60%	-6.85%
Max Drawdown (1Y) Largest decline over 1 year	-19.03%	-13.27%	-5.76%
Max Drawdown (3Y) Largest decline over 3 years	-22.10%	-38.66%	+16.56%
Max Drawdown (5Y) Largest decline over 5 years	-36.36%	-43.35%	+6.99%
Max Drawdown (10Y) Largest decline over 10 years	-36.36%	-43.35%	+6.99%
Current Drawdown Current decline from peak	-14.34%	-0.12%	-14.22%
Average Drawdown Average peak-to-trough decline	-11.32%	-10.89%	-0.43%
Ulcer Index Depth and duration of drawdowns from previous peaks	8.09%	3.90%	+4.19%

Volatility

BUFTX vs. NEEGX - Volatility Comparison

The current volatility for Buffalo Discovery Fund (BUFTX) is 3.88%, while Needham Growth Fund (NEEGX) has a volatility of 9.70%. This indicates that BUFTX experiences smaller price fluctuations and is considered to be less risky than NEEGX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	BUFTX	NEEGX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.88%	9.70%	-5.82%
Volatility (6M) Calculated over the trailing 6-month period	11.91%	20.88%	-8.97%
Volatility (1Y) Calculated over the trailing 1-year period	15.32%	27.12%	-11.80%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.07%	28.30%	-7.23%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	20.39%	25.28%	-4.89%

BUFTX vs. NEEGX - Expense Ratio Comparison

BUFTX has a 1.00% expense ratio, which is lower than NEEGX's 1.78% expense ratio.

Dividends

BUFTX vs. NEEGX - Dividend Comparison

BUFTX's dividend yield for the trailing twelve months is around 21.89%, more than NEEGX's 4.76% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
BUFTX Buffalo Discovery Fund	21.89%	21.15%	10.00%	0.00%	7.08%	15.11%	7.98%	14.81%	7.01%	4.64%	0.00%	7.56%
NEEGX Needham Growth Fund	4.76%	7.57%	3.92%	0.00%	1.78%	6.92%	5.73%	11.31%	17.79%	9.70%	4.22%	6.74%

Frequently Asked Questions

Can I hold both BUFTX and NEEGX in my portfolio?

BUFTX and NEEGX have a correlation of 0.69, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, BUFTX or NEEGX?

NEEGX has higher volatility (9.70%) compared to BUFTX (3.88%). In terms of maximum drawdown, BUFTX dropped -60.45% vs NEEGX's -53.60%.

Which has better risk-adjusted returns?

NEEGX currently has the higher Sharpe Ratio (3.61 vs -0.42), 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.