BUFSX vs. NEAIX

Last updated Jun 4, 2026

BUFSX (Buffalo Small Cap Fund) and NEAIX (Needham Aggressive Growth Fund Institutional Class) are both Small Cap Growth Equities funds. Over the past 5 years, BUFSX returned -3.30%/yr vs 24.27%/yr for NEAIX. Their correlation of 0.83 suggests significant overlap in exposure. BUFSX charges 1.01%/yr vs 1.20%/yr for NEAIX.

Performance

BUFSX vs. NEAIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Buffalo Small Cap Fund (BUFSX) and Needham Aggressive Growth Fund Institutional Class (NEAIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, BUFSX achieves a 12.85% return, which is significantly lower than NEAIX's 59.81% return.

BUFSX

• 1D: 1.15%
• 1M: 5.14%
• YTD: 12.85%
• 6M: 11.50%
• 1Y: 19.44%
• 3Y*: 6.33%
• 5Y*: -3.30%
• 10Y*: 10.83%

NEAIX

• 1D: 3.25%
• 1M: 17.12%
• YTD: 59.81%
• 6M: 61.32%
• 1Y: 97.17%
• 3Y*: 39.29%
• 5Y*: 24.27%
• 10Y*: —

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

BUFSX vs. NEAIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
BUFSX Buffalo Small Cap Fund	12.85%	-0.13%	5.38%	5.45%	-30.01%	4.44%	66.49%	40.97%	-5.73%	25.95%
NEAIX Needham Aggressive Growth Fund Institutional Class	59.81%	26.99%	14.86%	38.37%	-27.02%	38.46%	52.49%	44.68%	-15.64%	10.07%

Correlation

The correlation between BUFSX and NEAIX is 0.83, 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	0.83
Correlation (3Y) Calculated over the trailing 3-year period	0.82
Correlation (5Y) Calculated over the trailing 5-year period	0.84
Correlation (All Time) Calculated using the full available price history since Jan 4, 2017	0.83

The correlation between BUFSX and NEAIX has been stable across timeframes, ranging from 0.82 to 0.84 - a consistent structural relationship.

Return for Risk

BUFSX vs. NEAIX — Risk / Return Rank

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

BUFSX

BUFSX Risk / Return Rank: 17
BUFSX Sharpe Ratio Rank: 17
BUFSX Sortino Ratio Rank: 17
BUFSX Omega Ratio Rank: 15
BUFSX Calmar Ratio Rank: 17
BUFSX Martin Ratio Rank: 20

NEAIX

NEAIX Risk / Return Rank: 94
NEAIX Sharpe Ratio Rank: 98
NEAIX Sortino Ratio Rank: 91
NEAIX Omega Ratio Rank: 86
NEAIX Calmar Ratio Rank: 97
NEAIX Martin Ratio Rank: 98

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.

BUFSX vs. NEAIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Buffalo Small Cap Fund (BUFSX) and Needham Aggressive Growth Fund Institutional Class (NEAIX). 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.

	BUFSX	NEAIX	Difference
Sharpe ratio Return per unit of total volatility	1.15	3.94	-2.79
Sortino ratio Return per unit of downside risk	1.73	4.42	-2.69
Omega ratio Gain probability vs. loss probability	1.20	1.59	-0.39
Calmar ratio Return relative to maximum drawdown	1.46	7.27	-5.81
Martin ratio Return relative to average drawdown	5.37	29.35	-23.98
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

BUFSX vs. NEAIX - Sharpe Ratio Comparison

The current BUFSX Sharpe Ratio is 1.15, which is lower than the NEAIX Sharpe Ratio of 3.94. The chart below compares the historical Sharpe Ratios of BUFSX and NEAIX, 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

	BUFSX	NEAIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.15	3.94	-2.79
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	-0.14	0.99	-1.13
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.44	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.47	0.91	-0.45

Drawdowns

BUFSX vs. NEAIX - Drawdown Comparison

The maximum BUFSX drawdown since its inception was -53.24%, which is greater than NEAIX's maximum drawdown of -35.93%. Use the drawdown chart below to compare losses from any high point for BUFSX and NEAIX.

Drawdown Indicators

	BUFSX	NEAIX	Difference
Max Drawdown Largest peak-to-trough decline	-53.24%	-35.93%	-17.31%
Max Drawdown (1Y) Largest decline over 1 year	-14.92%	-13.98%	-0.94%
Max Drawdown (3Y) Largest decline over 3 years	-26.39%	-28.21%	+1.82%
Max Drawdown (5Y) Largest decline over 5 years	-46.57%	-35.93%	-10.64%
Max Drawdown (10Y) Largest decline over 10 years	-46.74%	—	—
Current Drawdown Current decline from peak	-23.13%	0.00%	-23.13%
Average Drawdown Average peak-to-trough decline	-12.91%	-8.60%	-4.31%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.05%	3.46%	+0.59%

Volatility

BUFSX vs. NEAIX - Volatility Comparison

The current volatility for Buffalo Small Cap Fund (BUFSX) is 5.20%, while Needham Aggressive Growth Fund Institutional Class (NEAIX) has a volatility of 10.14%. This indicates that BUFSX experiences smaller price fluctuations and is considered to be less risky than NEAIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	BUFSX	NEAIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	5.20%	10.14%	-4.94%
Volatility (6M) Calculated over the trailing 6-month period	13.68%	20.44%	-6.76%
Volatility (1Y) Calculated over the trailing 1-year period	18.96%	25.80%	-6.84%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	24.50%	24.58%	-0.08%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	24.57%	24.60%	-0.03%

BUFSX vs. NEAIX - Expense Ratio Comparison

BUFSX has a 1.01% expense ratio, which is lower than NEAIX's 1.20% expense ratio.

Dividends

BUFSX vs. NEAIX - Dividend Comparison

BUFSX has not paid dividends to shareholders, while NEAIX's dividend yield for the trailing twelve months is around 1.26%.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
BUFSX Buffalo Small Cap Fund	0.00%	0.00%	0.00%	0.00%	0.00%	13.53%	9.01%	9.14%	31.02%	30.30%	25.19%	70.18%
NEAIX Needham Aggressive Growth Fund Institutional Class	1.26%	2.01%	0.00%	0.00%	0.00%	6.84%	3.80%	10.42%	16.35%	5.14%	0.00%	0.00%

Frequently Asked Questions

Can I hold both BUFSX and NEAIX in my portfolio?

BUFSX and NEAIX have a correlation of 0.83, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, BUFSX or NEAIX?

NEAIX has higher volatility (10.14%) compared to BUFSX (5.20%). In terms of maximum drawdown, BUFSX dropped -53.24% vs NEAIX's -35.93%.

Which has better risk-adjusted returns?

NEAIX currently has the higher Sharpe Ratio (3.94 vs 1.15), 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.