MBB vs. CMBS
MBB (iShares MBS Bond ETF) and CMBS (iShares CMBS ETF) are both Mortgage Backed Securities funds from iShares - MBB tracks the Barclays Capital U.S. MBS Index while CMBS tracks the Barclays Capital U.S. CMBS (ERISA Only) Index. Both are passively managed. Over the past 10 years, MBB returned 1.30%/yr vs 2.06%/yr for CMBS. A 0.50 correlation means they provide meaningful diversification when combined. MBB charges 0.06%/yr vs 0.25%/yr for CMBS.
Performance
MBB vs. CMBS - Performance Comparison
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Returns By Period
In the year-to-date period, MBB achieves a 0.58% return, which is significantly higher than CMBS's 0.14% return. Over the past 10 years, MBB has underperformed CMBS with an annualized return of 1.30%, while CMBS has yielded a comparatively higher 2.06% annualized return.
MBB
- 1D
- -0.23%
- 1M
- 0.31%
- YTD
- 0.58%
- 6M
- 0.71%
- 1Y
- 6.76%
- 3Y*
- 4.36%
- 5Y*
- 0.34%
- 10Y*
- 1.30%
CMBS
- 1D
- -0.04%
- 1M
- -0.05%
- YTD
- 0.14%
- 6M
- 0.28%
- 1Y
- 4.26%
- 3Y*
- 5.15%
- 5Y*
- 0.79%
- 10Y*
- 2.06%
MBB vs. CMBS - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
MBB iShares MBS Bond ETF | 0.58% | 8.38% | 1.31% | 5.01% | -11.74% | -1.43% | 4.08% | 6.18% | 0.82% | 2.49% |
CMBS iShares CMBS ETF | 0.14% | 7.67% | 4.27% | 5.06% | -11.21% | -1.82% | 7.86% | 7.94% | 0.77% | 2.95% |
Correlation
The correlation between MBB and CMBS 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 (3Y) Calculated over the trailing 3-year period | 0.54 |
Correlation (5Y) Calculated over the trailing 5-year period | 0.63 |
Correlation (10Y) Calculated over the trailing 10-year period | 0.55 |
Correlation (All Time) Calculated using the full available price history since Feb 17, 2012 | 0.50 |
The correlation between MBB and CMBS shifts across timeframes, from 0.35 (1 year) to 0.63 (5 years), reflecting how their relationship changes across market environments.
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Return for Risk
MBB vs. CMBS — Risk / Return Rank
MBB
CMBS
MBB vs. CMBS - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for iShares MBS Bond ETF (MBB) and iShares CMBS ETF (CMBS). 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.
| MBB | CMBS | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | +0.35 | ||
| Sortino ratioReturn per unit of downside risk | +0.45 | ||
| Omega ratioGain probability vs. loss probability | 1.27 | 1.20 | +0.07 |
| Calmar ratioReturn relative to maximum drawdown | 2.31 | 1.76 | +0.55 |
| Martin ratioReturn relative to average drawdown | 7.64 | 4.90 | +2.74 |
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month. | |||
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Sharpe Ratios by Period
| MBB | CMBS | Difference | |
|---|---|---|---|
Sharpe Ratio (1Y)Calculated over the trailing 1-year period | 1.51 | 1.16 | +0.35 |
Sharpe Ratio (5Y)Calculated over the trailing 5-year period | 0.05 | 0.15 | -0.10 |
Sharpe Ratio (10Y)Calculated over the trailing 10-year period | 0.25 | 0.36 | -0.11 |
Sharpe Ratio (All Time)Calculated using the full available price history | 0.58 | 0.43 | +0.15 |
Drawdowns
MBB vs. CMBS - Drawdown Comparison
The maximum MBB drawdown since its inception was -17.64%, which is greater than CMBS's maximum drawdown of -15.87%. Use the drawdown chart below to compare losses from any high point for MBB and CMBS.
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Drawdown Indicators
| MBB | CMBS | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -17.64% | -15.87% | -1.77% |
Max Drawdown (1Y)Largest decline over 1 year | -2.94% | -2.44% | -0.50% |
Max Drawdown (3Y)Largest decline over 3 years | -7.68% | -3.29% | -4.39% |
Max Drawdown (5Y)Largest decline over 5 years | -17.19% | -15.87% | -1.32% |
Max Drawdown (10Y)Largest decline over 10 years | -17.64% | -15.87% | -1.77% |
Current DrawdownCurrent decline from peak | -1.52% | -1.77% | +0.25% |
Average DrawdownAverage peak-to-trough decline | -2.35% | -2.95% | +0.60% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 0.89% | 0.87% | +0.02% |
Volatility
MBB vs. CMBS - Volatility Comparison
iShares MBS Bond ETF (MBB) has a higher volatility of 1.59% compared to iShares CMBS ETF (CMBS) at 1.11%. This indicates that MBB's price experiences larger fluctuations and is considered to be riskier than CMBS based on this measure. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| MBB | CMBS | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 1.59% | 1.11% | +0.48% |
Volatility (6M)Calculated over the trailing 6-month period | 3.23% | 2.82% | +0.41% |
Volatility (1Y)Calculated over the trailing 1-year period | 4.51% | 3.71% | +0.80% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 6.81% | 5.31% | +1.50% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 5.31% | 5.77% | -0.46% |
MBB vs. CMBS - Expense Ratio Comparison
MBB has a 0.06% expense ratio, which is lower than CMBS's 0.25% expense ratio. Despite the difference, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.
Dividends
MBB vs. CMBS - Dividend Comparison
MBB's dividend yield for the trailing twelve months is around 4.28%, more than CMBS's 3.58% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
CMBS iShares CMBS ETF | 3.58% | 3.45% | 3.31% | 2.97% | 2.65% | 2.46% | 2.83% | 2.74% | 2.70% | 2.50% | 2.29% | 2.31% |
MBB iShares MBS Bond ETF | 4.28% | 4.21% | 3.94% | 3.40% | 2.31% | 1.05% | 2.10% | 2.77% | 2.64% | 2.23% | 2.58% | 2.66% |
Frequently Asked Questions
MBB and CMBS 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.
MBB has higher volatility (1.59%) compared to CMBS (1.11%). In terms of maximum drawdown, MBB dropped -17.64% vs CMBS's -15.87%.
On 10-year performance, CMBS leads with 2.06% vs 1.30% for MBB. On fees, MBB is cheaper at 0.06% per year. On volatility, CMBS has been the lower-risk option at 1.11%. The better choice depends on whether you care most about return, fees, risk, or income.
Over the 10-year period, CMBS has performed better with a 2.06% return vs 1.30%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.
MBB is cheaper with a 0.06% expense ratio, compared with 0.25% for CMBS.
MBB has the higher dividend yield at 4.28%, compared with 3.58% for CMBS.
MBB tracks Barclays Capital U.S. MBS Index, while CMBS tracks Barclays Capital U.S. CMBS (ERISA Only) Index. Their fees differ too: 0.06% for MBB and 0.25% for CMBS.
MBB currently has the higher Sharpe Ratio (1.51 vs 1.16), 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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