FUMBX vs. DBLSX

Last updated Jun 25, 2026

FUMBX (Fidelity Short-Term Treasury Bond Index Fund) and DBLSX (DoubleLine Low Duration Bond Fund) are both Short-Term Bond funds. Over the past 5 years, FUMBX returned 1.33%/yr vs 3.19%/yr for DBLSX. A 0.63 correlation means they provide meaningful diversification when combined. FUMBX charges 0.03%/yr vs 0.41%/yr for DBLSX.

Performance

FUMBX vs. DBLSX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Fidelity Short-Term Treasury Bond Index Fund (FUMBX) and DoubleLine Low Duration Bond Fund (DBLSX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, FUMBX achieves a -0.01% return, which is significantly lower than DBLSX's 1.17% return.

FUMBX

• 1D: 0.10%
• 1M: 0.26%
• YTD: -0.01%
• 6M: 0.34%
• 1Y: 2.69%
• 3Y*: 4.07%
• 5Y*: 1.33%
• 10Y*: —

DBLSX

• 1D: 0.10%
• 1M: 0.35%
• YTD: 1.17%
• 6M: 1.27%
• 1Y: 3.97%
• 3Y*: 5.44%
• 5Y*: 3.19%
• 10Y*: 2.85%

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

FUMBX vs. DBLSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
FUMBX Fidelity Short-Term Treasury Bond Index Fund	-0.01%	5.83%	3.25%	4.47%	-5.84%	-1.38%	4.22%	4.19%	1.47%	-0.33%
DBLSX DoubleLine Low Duration Bond Fund	1.17%	5.74%	5.32%	6.76%	-2.69%	0.70%	2.02%	4.73%	1.40%	0.23%

Correlation

The correlation between FUMBX and DBLSX is 0.72, 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	0.72
Correlation (3Y) Calculated over the trailing 3-year period	0.72
Correlation (5Y) Calculated over the trailing 5-year period	0.74
Correlation (All Time) Calculated using the full available price history since Oct 19, 2017	0.63

The correlation between FUMBX and DBLSX shifts across timeframes, from 0.63 (all time) to 0.74 (5 years), reflecting how their relationship changes across market environments.

Return for Risk

FUMBX vs. DBLSX — Risk / Return Rank

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

FUMBX

FUMBX Risk / Return Rank: 28
FUMBX Sharpe Ratio Rank: 27
FUMBX Sortino Ratio Rank: 31
FUMBX Omega Ratio Rank: 31
FUMBX Calmar Ratio Rank: 28
FUMBX Martin Ratio Rank: 24

DBLSX

DBLSX Risk / Return Rank: 97
DBLSX Sharpe Ratio Rank: 97
DBLSX Sortino Ratio Rank: 97
DBLSX Omega Ratio Rank: 97
DBLSX Calmar Ratio Rank: 96
DBLSX Martin Ratio Rank: 97

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.

FUMBX vs. DBLSX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity Short-Term Treasury Bond Index Fund (FUMBX) and DoubleLine Low Duration Bond Fund (DBLSX). 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.

	FUMBX	DBLSX	Difference
Sharpe ratio: Return per unit of total volatility	1.35	3.41	-2.06
Sortino ratio: Return per unit of downside risk	2.12	5.53	-3.41
Omega ratio: Gain probability vs. loss probability	1.27	1.93	-0.66
Calmar ratio: Return relative to maximum drawdown	1.82	5.67	-3.85
Martin ratio: Return relative to average drawdown	5.33	25.87	-20.54

FUMBX vs. DBLSX - Sharpe Ratio Comparison

The current FUMBX Sharpe Ratio is 1.35, which is lower than the DBLSX Sharpe Ratio of 3.41. The chart below compares the historical Sharpe Ratios of FUMBX and DBLSX, 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

FUMBX vs. DBLSX - Drawdown Comparison

The maximum FUMBX drawdown since its inception was -8.83%, smaller than the maximum DBLSX drawdown of -57.22%. Use the drawdown chart below to compare losses from any high point for FUMBX and DBLSX.

Drawdown Indicators

	FUMBX	DBLSX	Difference
Max Drawdown Largest peak-to-trough decline	-8.83%	-57.22%	+48.39%
Max Drawdown (1Y) Largest decline over 1 year	-1.54%	-0.72%	-0.82%
Max Drawdown (3Y) Largest decline over 3 years	-1.57%	-0.72%	-0.85%
Max Drawdown (5Y) Largest decline over 5 years	-8.60%	-4.71%	-3.89%
Max Drawdown (10Y) Largest decline over 10 years	—	-57.22%	—
Current Drawdown Current decline from peak	-0.96%	-44.94%	+43.98%
Average Drawdown Average peak-to-trough decline	-1.85%	-31.56%	+29.71%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.52%	0.16%	+0.36%

Volatility

FUMBX vs. DBLSX - Volatility Comparison

Fidelity Short-Term Treasury Bond Index Fund (FUMBX) has a higher volatility of 0.71% compared to DoubleLine Low Duration Bond Fund (DBLSX) at 0.38%. This indicates that FUMBX's price experiences larger fluctuations and is considered to be riskier than DBLSX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FUMBX	DBLSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.71%	0.38%	+0.33%
Volatility (6M) Calculated over the trailing 6-month period	1.56%	0.92%	+0.64%
Volatility (1Y) Calculated over the trailing 1-year period	2.08%	1.20%	+0.88%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	2.93%	1.40%	+1.53%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	2.49%	64.00%	-61.51%

FUMBX vs. DBLSX - Expense Ratio Comparison

FUMBX has a 0.03% expense ratio, which is lower than DBLSX's 0.41% expense ratio.

Dividends

FUMBX vs. DBLSX - Dividend Comparison

FUMBX's dividend yield for the trailing twelve months is around 3.77%, less than DBLSX's 4.54% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
DBLSX DoubleLine Low Duration Bond Fund	4.54%	4.64%	5.09%	4.49%	2.50%	1.72%	2.37%	3.21%	2.92%	2.42%	2.52%	2.47%
FUMBX Fidelity Short-Term Treasury Bond Index Fund	3.77%	3.51%	2.91%	1.64%	0.86%	1.15%	1.41%	1.88%	1.64%	0.34%	0.00%	0.00%

Frequently Asked Questions

Can I hold both FUMBX and DBLSX in my portfolio?

FUMBX and DBLSX have a correlation of 0.72, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, FUMBX or DBLSX?

FUMBX has higher volatility (0.71%) compared to DBLSX (0.38%). In terms of maximum drawdown, FUMBX dropped -8.83% vs DBLSX's -57.22%.

Which has better risk-adjusted returns?

DBLSX currently has the higher Sharpe Ratio (3.41 vs 1.35), 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.