FNSOX vs. FUMBX

Last updated Jun 24, 2026

FNSOX (Fidelity Short-Term Bond Index Fund) and FUMBX (Fidelity Short-Term Treasury Bond Index Fund) are both mutual funds - FNSOX is a Total Bond Market fund managed by Fidelity, while FUMBX is a Short-Term Bond fund tracking the Bloomberg U.S. 1-5 Year Treasury Bond Index. Over the past 5 years, FNSOX returned 1.59%/yr vs 1.31%/yr for FUMBX. Their correlation of 0.88 suggests significant overlap in exposure. Both charge a 0.03% expense ratio.

Performance

FNSOX vs. FUMBX - Performance Comparison

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

Returns By Period

In the year-to-date period, FNSOX achieves a 0.07% return, which is significantly higher than FUMBX's -0.11% return.

FNSOX

• 1D: -0.10%
• 1M: 0.17%
• YTD: 0.07%
• 6M: 0.42%
• 1Y: 3.05%
• 3Y*: 4.48%
• 5Y*: 1.59%
• 10Y*: —

FUMBX

• 1D: -0.10%
• 1M: 0.16%
• YTD: -0.11%
• 6M: 0.24%
• 1Y: 2.69%
• 3Y*: 4.03%
• 5Y*: 1.31%
• 10Y*: —

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

FNSOX vs. FUMBX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
FNSOX Fidelity Short-Term Bond Index Fund	0.07%	6.01%	3.90%	4.90%	-5.76%	-1.25%	4.28%	4.95%	1.14%	-0.22%
FUMBX Fidelity Short-Term Treasury Bond Index Fund	-0.11%	5.83%	3.25%	4.47%	-5.84%	-1.38%	4.22%	4.19%	1.47%	-0.24%

Correlation

The correlation between FNSOX and FUMBX is 0.90, 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	0.90
Correlation (3Y) Calculated over the trailing 3-year period	0.91
Correlation (5Y) Calculated over the trailing 5-year period	0.93
Correlation (All Time) Calculated using the full available price history since Oct 31, 2017	0.88

The correlation between FNSOX and FUMBX has been stable across timeframes, ranging from 0.88 to 0.93 - a consistent structural relationship.

Return for Risk

FNSOX vs. FUMBX — Risk / Return Rank

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

FNSOX

FNSOX Risk / Return Rank: 38
FNSOX Sharpe Ratio Rank: 35
FNSOX Sortino Ratio Rank: 43
FNSOX Omega Ratio Rank: 40
FNSOX Calmar Ratio Rank: 38
FNSOX Martin Ratio Rank: 32

FUMBX

FUMBX Risk / Return Rank: 29
FUMBX Sharpe Ratio Rank: 27
FUMBX Sortino Ratio Rank: 32
FUMBX Omega Ratio Rank: 32
FUMBX Calmar Ratio Rank: 29
FUMBX Martin Ratio Rank: 25

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.

FNSOX vs. FUMBX - Risk-Adjusted Trends Comparison

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

	FNSOX	FUMBX	Difference
Sharpe ratio: Return per unit of total volatility	1.57	1.39	+0.18
Sortino ratio: Return per unit of downside risk	2.52	2.19	+0.33
Omega ratio: Gain probability vs. loss probability	1.31	1.28	+0.03
Calmar ratio: Return relative to maximum drawdown	2.22	1.89	+0.33
Martin ratio: Return relative to average drawdown	6.88	5.55	+1.33

FNSOX vs. FUMBX - Sharpe Ratio Comparison

The current FNSOX Sharpe Ratio is 1.57, which is comparable to the FUMBX Sharpe Ratio of 1.39. The chart below compares the historical Sharpe Ratios of FNSOX and FUMBX, 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

FNSOX vs. FUMBX - Drawdown Comparison

The maximum FNSOX drawdown since its inception was -8.92%, roughly equal to the maximum FUMBX drawdown of -8.83%. Use the drawdown chart below to compare losses from any high point for FNSOX and FUMBX.

Drawdown Indicators

	FNSOX	FUMBX	Difference
Max Drawdown Largest peak-to-trough decline	-8.92%	-8.83%	-0.09%
Max Drawdown (1Y) Largest decline over 1 year	-1.47%	-1.54%	+0.07%
Max Drawdown (3Y) Largest decline over 3 years	-1.51%	-1.57%	+0.06%
Max Drawdown (5Y) Largest decline over 5 years	-8.77%	-8.60%	-0.17%
Current Drawdown Current decline from peak	-0.90%	-1.06%	+0.16%
Average Drawdown Average peak-to-trough decline	-1.73%	-1.85%	+0.12%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.47%	0.52%	-0.05%

Volatility

FNSOX vs. FUMBX - Volatility Comparison

Fidelity Short-Term Bond Index Fund (FNSOX) and Fidelity Short-Term Treasury Bond Index Fund (FUMBX) have volatilities of 0.71% and 0.70%, respectively, indicating that both stocks experience similar levels of price fluctuations. This suggests that the risk associated with both stocks, as measured by volatility, is nearly the same. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FNSOX	FUMBX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.71%	0.70%	+0.01%
Volatility (6M) Calculated over the trailing 6-month period	1.56%	1.56%	0.00%
Volatility (1Y) Calculated over the trailing 1-year period	2.08%	2.08%	0.00%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	2.90%	2.93%	-0.03%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	2.47%	2.49%	-0.02%

FNSOX vs. FUMBX - Expense Ratio Comparison

Both FNSOX and FUMBX have an expense ratio of 0.03%, making them cost-effective options compared to the broader market, where average expense ratios typically range from 0.3% to 0.9%.

Dividends

FNSOX vs. FUMBX - Dividend Comparison

FNSOX's dividend yield for the trailing twelve months is around 3.54%, less than FUMBX's 3.77% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017
FNSOX Fidelity Short-Term Bond Index Fund	3.54%	3.22%	2.80%	1.74%	0.81%	0.80%	1.54%	2.61%	2.04%	0.34%
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%

Frequently Asked Questions

Can I hold both FNSOX and FUMBX in my portfolio?

With a correlation of 0.90, FNSOX and FUMBX 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, FNSOX or FUMBX?

FNSOX has higher volatility (0.71%) compared to FUMBX (0.70%). In terms of maximum drawdown, FNSOX dropped -8.92% vs FUMBX's -8.83%.

Which has better risk-adjusted returns?

FNSOX currently has the higher Sharpe Ratio (1.57 vs 1.39), 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.