ISTB vs. FUMBX
ISTB (iShares Core 1-5 Year USD Bond ETF) and FUMBX (Fidelity Short-Term Treasury Bond Index Fund) are both Short-Term Bond funds - ISTB tracks the BBG US Universal 1-5 Year Index (USD) while FUMBX tracks the Bloomberg U.S. 1-5 Year Treasury Bond Index. Both are passively managed. Over the past 5 years, ISTB returned 1.91%/yr vs 1.31%/yr for FUMBX. A 0.78 correlation means they provide meaningful diversification when combined. ISTB charges 0.06%/yr vs 0.03%/yr for FUMBX.
Performance
ISTB vs. FUMBX - Performance Comparison
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Returns By Period
In the year-to-date period, ISTB achieves a 0.53% return, which is significantly higher than FUMBX's -0.11% return.
ISTB
- 1D
- 0.08%
- 1M
- 0.27%
- YTD
- 0.53%
- 6M
- 0.69%
- 1Y
- 3.65%
- 3Y*
- 5.01%
- 5Y*
- 1.91%
- 10Y*
- 2.24%
FUMBX
- 1D
- -0.10%
- 1M
- 0.16%
- YTD
- -0.11%
- 6M
- 0.24%
- 1Y
- 2.69%
- 3Y*
- 4.03%
- 5Y*
- 1.31%
- 10Y*
- —
ISTB vs. FUMBX - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
ISTB iShares Core 1-5 Year USD Bond ETF | 0.53% | 6.36% | 4.37% | 5.56% | -6.08% | -0.71% | 4.75% | 5.61% | 1.02% | -0.15% |
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% | -0.33% |
Correlation
The correlation between ISTB and FUMBX 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 | 0.87 |
Correlation (5Y) Calculated over the trailing 5-year period | 0.88 |
Correlation (All Time) Calculated using the full available price history since Oct 19, 2017 | 0.78 |
The correlation between ISTB and FUMBX shifts across timeframes, from 0.78 (all time) to 0.88 (5 years), reflecting how their relationship changes across market environments.
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Return for Risk
ISTB vs. FUMBX — Risk / Return Rank
ISTB
FUMBX
ISTB vs. FUMBX - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for iShares Core 1-5 Year USD Bond ETF (ISTB) 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.
| ISTB | FUMBX | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | +0.66 | ||
| Sortino ratioReturn per unit of downside risk | +0.95 | ||
| Omega ratioGain probability vs. loss probability | 1.39 | 1.28 | +0.11 |
| Calmar ratioReturn relative to maximum drawdown | 2.91 | 1.89 | +1.03 |
| Martin ratioReturn relative to average drawdown | 10.69 | 5.55 | +5.14 |
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Drawdowns
ISTB vs. FUMBX - Drawdown Comparison
The maximum ISTB drawdown since its inception was -9.34%, which is greater than FUMBX's maximum drawdown of -8.83%. Use the drawdown chart below to compare losses from any high point for ISTB and FUMBX.
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Drawdown Indicators
| ISTB | FUMBX | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -9.34% | -8.83% | -0.51% |
Max Drawdown (1Y)Largest decline over 1 year | -1.26% | -1.54% | +0.28% |
Max Drawdown (3Y)Largest decline over 3 years | -1.36% | -1.57% | +0.21% |
Max Drawdown (5Y)Largest decline over 5 years | -9.34% | -8.60% | -0.74% |
Max Drawdown (10Y)Largest decline over 10 years | -9.34% | — | — |
Current DrawdownCurrent decline from peak | -0.38% | -1.06% | +0.68% |
Average DrawdownAverage peak-to-trough decline | -1.22% | -1.85% | +0.63% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 0.34% | 0.52% | -0.18% |
Volatility
ISTB vs. FUMBX - Volatility Comparison
The current volatility for iShares Core 1-5 Year USD Bond ETF (ISTB) is 0.64%, while Fidelity Short-Term Treasury Bond Index Fund (FUMBX) has a volatility of 0.70%. This indicates that ISTB experiences smaller price fluctuations and is considered to be less risky than FUMBX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| ISTB | FUMBX | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 0.64% | 0.70% | -0.06% |
Volatility (6M)Calculated over the trailing 6-month period | 1.36% | 1.56% | -0.20% |
Volatility (1Y)Calculated over the trailing 1-year period | 1.79% | 2.08% | -0.29% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 2.80% | 2.93% | -0.13% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 2.51% | 2.49% | +0.02% |
ISTB vs. FUMBX - Expense Ratio Comparison
ISTB has a 0.06% expense ratio, which is higher than FUMBX's 0.03% expense ratio. However, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.
Dividends
ISTB vs. FUMBX - Dividend Comparison
ISTB's dividend yield for the trailing twelve months is around 4.25%, more than FUMBX's 3.77% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
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% |
ISTB iShares Core 1-5 Year USD Bond ETF | 4.25% | 4.12% | 3.83% | 2.97% | 2.01% | 1.69% | 2.20% | 2.75% | 2.57% | 2.06% | 1.90% | 1.58% |
Frequently Asked Questions
ISTB and FUMBX 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.
FUMBX has higher volatility (0.70%) compared to ISTB (0.64%). In terms of maximum drawdown, ISTB dropped -9.34% vs FUMBX's -8.83%.
ISTB currently has the higher Sharpe Ratio (2.05 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.
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