EFFI vs. BUFI

Last updated Jun 23, 2026

EFFI (Harbor Osmosis International Resource Efficient ETF) and BUFI (AB International Buffer ETF) are both exchange-traded funds - EFFI is a Foreign Large Cap Equities fund actively managed by Harbor, while BUFI is a Defined Outcome fund actively managed by AllianceBernstein. Both are actively managed. Over the past year, EFFI returned 20.38% vs 14.67% for BUFI. Their correlation of 0.92 suggests significant overlap in exposure. EFFI charges 0.55%/yr vs 0.69%/yr for BUFI.

Performance

EFFI vs. BUFI - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Harbor Osmosis International Resource Efficient ETF (EFFI) and AB International Buffer ETF (BUFI). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, EFFI achieves a 5.11% return, which is significantly lower than BUFI's 6.10% return.

EFFI

• 1D: -0.00%
• 1M: 0.41%
• YTD: 5.11%
• 6M: 5.37%
• 1Y: 20.38%
• 3Y*: —
• 5Y*: —
• 10Y*: —

BUFI

• 1D: 0.16%
• 1M: 1.31%
• YTD: 6.10%
• 6M: 6.39%
• 1Y: 14.67%
• 3Y*: —
• 5Y*: —
• 10Y*: —

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

EFFI vs. BUFI - Yearly Performance Comparison

	2026 (YTD)	2025	2024
EFFI Harbor Osmosis International Resource Efficient ETF	5.11%	33.41%	-3.24%
BUFI AB International Buffer ETF	6.10%	16.50%	-1.52%

Correlation

The correlation between EFFI and BUFI is 0.92, 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	0.92
Correlation (All Time) Calculated using the full available price history since Dec 12, 2024	0.92

The correlation between EFFI and BUFI has been stable across timeframes, ranging from 0.92 to 0.92 - a consistent structural relationship.

Return for Risk

EFFI vs. BUFI — Risk / Return Rank

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

EFFI

EFFI Risk / Return Rank: 41
EFFI Sharpe Ratio Rank: 41
EFFI Sortino Ratio Rank: 39
EFFI Omega Ratio Rank: 39
EFFI Calmar Ratio Rank: 40
EFFI Martin Ratio Rank: 45

BUFI

BUFI Risk / Return Rank: 55
BUFI Sharpe Ratio Rank: 52
BUFI Sortino Ratio Rank: 54
BUFI Omega Ratio Rank: 56
BUFI Calmar Ratio Rank: 54
BUFI Martin Ratio Rank: 60

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.

EFFI vs. BUFI - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Harbor Osmosis International Resource Efficient ETF (EFFI) and AB International Buffer ETF (BUFI). 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.

	EFFI	BUFI	Difference
Sharpe ratio: Return per unit of total volatility	1.38	1.72	-0.34
Sortino ratio: Return per unit of downside risk	1.94	2.53	-0.59
Omega ratio: Gain probability vs. loss probability	1.25	1.34	-0.09
Calmar ratio: Return relative to maximum drawdown	1.94	2.59	-0.65
Martin ratio: Return relative to average drawdown	7.21	10.30	-3.10

EFFI vs. BUFI - Sharpe Ratio Comparison

The current EFFI Sharpe Ratio is 1.38, which is comparable to the BUFI Sharpe Ratio of 1.72. The chart below compares the historical Sharpe Ratios of EFFI and BUFI, 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

EFFI vs. BUFI - Drawdown Comparison

The maximum EFFI drawdown since its inception was -13.64%, which is greater than BUFI's maximum drawdown of -7.43%. Use the drawdown chart below to compare losses from any high point for EFFI and BUFI.

Drawdown Indicators

	EFFI	BUFI	Difference
Max Drawdown Largest peak-to-trough decline	-13.64%	-7.43%	-6.21%
Max Drawdown (1Y) Largest decline over 1 year	-10.55%	-5.69%	-4.86%
Current Drawdown Current decline from peak	-1.05%	0.00%	-1.05%
Average Drawdown Average peak-to-trough decline	-1.80%	-0.84%	-0.96%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.84%	1.43%	+1.41%

Volatility

EFFI vs. BUFI - Volatility Comparison

Harbor Osmosis International Resource Efficient ETF (EFFI) has a higher volatility of 3.67% compared to AB International Buffer ETF (BUFI) at 2.16%. This indicates that EFFI's price experiences larger fluctuations and is considered to be riskier than BUFI based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	EFFI	BUFI	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.67%	2.16%	+1.51%
Volatility (6M) Calculated over the trailing 6-month period	12.22%	7.27%	+4.95%
Volatility (1Y) Calculated over the trailing 1-year period	14.86%	8.58%	+6.28%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	16.53%	9.14%	+7.39%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	16.53%	9.14%	+7.39%

EFFI vs. BUFI - Expense Ratio Comparison

EFFI has a 0.55% expense ratio, which is lower than BUFI's 0.69% expense ratio.

Dividends

EFFI vs. BUFI - Dividend Comparison

EFFI's dividend yield for the trailing twelve months is around 4.12%, while BUFI has not paid dividends to shareholders.

Position	TTM	2025
BUFI AB International Buffer ETF	0.00%	0.00%
EFFI Harbor Osmosis International Resource Efficient ETF	4.12%	4.33%

Frequently Asked Questions

Can I hold both EFFI and BUFI in my portfolio?

With a correlation of 0.92, EFFI and BUFI move almost identically. Holding both adds very little diversification - you're essentially doubling your position in the same market segment. Choosing one is usually more capital-efficient.

Which is riskier, EFFI or BUFI?

EFFI has higher volatility (3.67%) compared to BUFI (2.16%). In terms of maximum drawdown, EFFI dropped -13.64% vs BUFI's -7.43%.

Which ETF is better, EFFI or BUFI?

On 1-year performance, EFFI leads with 20.38% vs 14.67% for BUFI. On fees, EFFI is cheaper at 0.55% per year. On volatility, BUFI has been the lower-risk option at 2.16%. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF has performed better, EFFI or BUFI?

Over the 1-year period, EFFI has performed better with a 20.38% return vs 14.67%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

Which ETF is cheaper, EFFI or BUFI?

EFFI is cheaper with a 0.55% expense ratio, compared with 0.69% for BUFI.

Which ETF pays a higher dividend yield, EFFI or BUFI?

EFFI has the higher dividend yield at 4.12%, compared with 0.00% for BUFI.

What is the main difference between EFFI and BUFI?

EFFI is categorized as Foreign Large Cap Equities, while BUFI is Defined Outcome. They also come from different issuers: Harbor and AllianceBernstein. Their fees differ too: 0.55% for EFFI and 0.69% for BUFI.

Which has better risk-adjusted returns?

BUFI currently has the higher Sharpe Ratio (1.72 vs 1.38), 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.