SDFI vs. FLDB

Last updated Jun 23, 2026

SDFI (AB Short Duration Income ETF) and FLDB (Fidelity Low Duration Bond ETF) are both Short-Term Bond funds. SDFI is passively managed, while FLDB is actively managed. Over the past year, SDFI returned 4.06% vs 4.09% for FLDB. At a 0.28 correlation, their price movements are largely independent. SDFI charges 0.30%/yr vs 0.20%/yr for FLDB.

Performance

SDFI vs. FLDB - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in AB Short Duration Income ETF (SDFI) and Fidelity Low Duration Bond ETF (FLDB). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, SDFI achieves a 0.86% return, which is significantly lower than FLDB's 1.53% return.

SDFI

• 1D: -0.06%
• 1M: 0.18%
• YTD: 0.86%
• 6M: 1.16%
• 1Y: 4.06%
• 3Y*: —
• 5Y*: —
• 10Y*: —

FLDB

• 1D: -0.04%
• 1M: 0.30%
• YTD: 1.53%
• 6M: 1.63%
• 1Y: 4.09%
• 3Y*: —
• 5Y*: —
• 10Y*: —

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

SDFI vs. FLDB - Yearly Performance Comparison

	2026 (YTD)	2025	2024
SDFI AB Short Duration Income ETF	0.86%	6.39%	3.73%
FLDB Fidelity Low Duration Bond ETF	1.53%	4.93%	2.85%

Correlation

The correlation between SDFI and FLDB is 0.35, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.35
Correlation (All Time) Calculated using the full available price history since Jun 10, 2024	0.28

Return for Risk

SDFI vs. FLDB — Risk / Return Rank

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

SDFI

SDFI Risk / Return Rank: 68
SDFI Sharpe Ratio Rank: 62
SDFI Sortino Ratio Rank: 66
SDFI Omega Ratio Rank: 69
SDFI Calmar Ratio Rank: 70
SDFI Martin Ratio Rank: 75

FLDB

FLDB Risk / Return Rank: 98
FLDB Sharpe Ratio Rank: 97
FLDB Sortino Ratio Rank: 98
FLDB Omega Ratio Rank: 98
FLDB Calmar Ratio Rank: 99
FLDB Martin Ratio Rank: 99

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.

SDFI vs. FLDB - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for AB Short Duration Income ETF (SDFI) and Fidelity Low Duration Bond ETF (FLDB). 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.

	SDFI	FLDB	Difference
Sharpe ratio: Return per unit of total volatility	1.98	4.47	-2.49
Sortino ratio: Return per unit of downside risk	2.93	8.02	-5.09
Omega ratio: Gain probability vs. loss probability	1.39	2.05	-0.65
Calmar ratio: Return relative to maximum drawdown	3.39	24.53	-21.14
Martin ratio: Return relative to average drawdown	13.75	90.01	-76.27

SDFI vs. FLDB - Sharpe Ratio Comparison

The current SDFI Sharpe Ratio is 1.98, which is lower than the FLDB Sharpe Ratio of 4.47. The chart below compares the historical Sharpe Ratios of SDFI and FLDB, 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

SDFI vs. FLDB - Drawdown Comparison

The maximum SDFI drawdown since its inception was -1.21%, which is greater than FLDB's maximum drawdown of -0.49%. Use the drawdown chart below to compare losses from any high point for SDFI and FLDB.

Drawdown Indicators

	SDFI	FLDB	Difference
Max Drawdown Largest peak-to-trough decline	-1.21%	-0.49%	-0.72%
Max Drawdown (1Y) Largest decline over 1 year	-1.20%	-0.17%	-1.03%
Current Drawdown Current decline from peak	-0.23%	-0.07%	-0.16%
Average Drawdown Average peak-to-trough decline	-0.22%	-0.05%	-0.17%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.30%	0.05%	+0.25%

Volatility

SDFI vs. FLDB - Volatility Comparison

AB Short Duration Income ETF (SDFI) has a higher volatility of 0.61% compared to Fidelity Low Duration Bond ETF (FLDB) at 0.37%. This indicates that SDFI's price experiences larger fluctuations and is considered to be riskier than FLDB based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	SDFI	FLDB	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.61%	0.37%	+0.24%
Volatility (6M) Calculated over the trailing 6-month period	1.40%	0.64%	+0.76%
Volatility (1Y) Calculated over the trailing 1-year period	2.06%	0.92%	+1.14%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	2.48%	1.31%	+1.17%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	2.48%	1.31%	+1.17%

SDFI vs. FLDB - Expense Ratio Comparison

SDFI has a 0.30% expense ratio, which is higher than FLDB's 0.20% expense ratio.

Dividends

SDFI vs. FLDB - Dividend Comparison

SDFI's dividend yield for the trailing twelve months is around 4.61%, more than FLDB's 4.44% yield.

Position	TTM	2025	2024
FLDB Fidelity Low Duration Bond ETF	4.44%	4.72%	3.58%
SDFI AB Short Duration Income ETF	4.61%	4.66%	3.11%

Frequently Asked Questions

Can I hold both SDFI and FLDB in my portfolio?

SDFI and FLDB have a correlation of 0.35, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, SDFI or FLDB?

SDFI has higher volatility (0.61%) compared to FLDB (0.37%). In terms of maximum drawdown, SDFI dropped -1.21% vs FLDB's -0.49%.

Which ETF is better, SDFI or FLDB?

On 1-year performance, FLDB leads with 4.09% vs 4.06% for SDFI. On fees, FLDB is cheaper at 0.20% per year. On volatility, FLDB has been the lower-risk option at 0.37%. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF has performed better, SDFI or FLDB?

Over the 1-year period, FLDB has performed better with a 4.09% return vs 4.06%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

Which ETF is cheaper, SDFI or FLDB?

FLDB is cheaper with a 0.20% expense ratio, compared with 0.30% for SDFI.

Which ETF pays a higher dividend yield, SDFI or FLDB?

SDFI has the higher dividend yield at 4.61%, compared with 4.44% for FLDB.

What is the main difference between SDFI and FLDB?

They also come from different issuers: AllianceBernstein and Fidelity. Their fees differ too: 0.30% for SDFI and 0.20% for FLDB.

Which has better risk-adjusted returns?

FLDB currently has the higher Sharpe Ratio (4.47 vs 1.98), 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.