SPMB vs. CMBS
SPMB (SPDR Portfolio Mortgage Backed Bond ETF) and CMBS (iShares CMBS ETF) are both Mortgage Backed Securities funds - SPMB tracks the Bloomberg US Aggregate Securitized - MBS while CMBS tracks the Barclays Capital U.S. CMBS (ERISA Only) Index. Both are passively managed. Over the past 10 years, SPMB returned 1.34%/yr vs 2.04%/yr for CMBS. At a 0.44 correlation, their price movements are largely independent. SPMB charges 0.04%/yr vs 0.25%/yr for CMBS.
Performance
SPMB vs. CMBS - Performance Comparison
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Returns By Period
In the year-to-date period, SPMB achieves a 1.33% return, which is significantly higher than CMBS's 0.51% return. Over the past 10 years, SPMB has underperformed CMBS with an annualized return of 1.34%, while CMBS has yielded a comparatively higher 2.04% annualized return.
SPMB
- 1D
- 0.45%
- 1M
- 1.22%
- YTD
- 1.33%
- 6M
- 1.17%
- 1Y
- 6.08%
- 3Y*
- 4.46%
- 5Y*
- 0.51%
- 10Y*
- 1.34%
CMBS
- 1D
- 0.12%
- 1M
- 0.56%
- YTD
- 0.51%
- 6M
- 0.47%
- 1Y
- 3.81%
- 3Y*
- 5.36%
- 5Y*
- 0.81%
- 10Y*
- 2.04%
SPMB vs. CMBS - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
SPMB SPDR Portfolio Mortgage Backed Bond ETF | 1.33% | 8.29% | 1.35% | 5.09% | -12.05% | -1.46% | 4.19% | 6.16% | 1.01% | 2.13% |
CMBS iShares CMBS ETF | 0.51% | 7.67% | 4.27% | 5.06% | -11.21% | -1.82% | 7.86% | 7.94% | 0.77% | 2.95% |
Correlation
The correlation between SPMB and CMBS is 0.37, which is low. Their price movements are largely independent, making them effective diversification partners.
| Correlation | |
|---|---|
Correlation (1Y) Calculated over the trailing 1-year period | 0.37 |
Correlation (3Y) Calculated over the trailing 3-year period | 0.54 |
Correlation (5Y) Calculated over the trailing 5-year period | 0.64 |
Correlation (10Y) Calculated over the trailing 10-year period | 0.52 |
Correlation (All Time) Calculated using the full available price history since Feb 16, 2012 | 0.44 |
The correlation between SPMB and CMBS shifts across timeframes, from 0.37 (1 year) to 0.64 (5 years), reflecting how their relationship changes across market environments.
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Return for Risk
SPMB vs. CMBS — Risk / Return Rank
SPMB
CMBS
SPMB vs. CMBS - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for SPDR Portfolio Mortgage Backed Bond ETF (SPMB) 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.
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.
| SPMB | CMBS | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | +0.40 | ||
| Sortino ratioReturn per unit of downside risk | +0.57 | ||
| Omega ratioGain probability vs. loss probability | 1.26 | 1.18 | +0.08 |
| Calmar ratioReturn relative to maximum drawdown | 2.11 | 1.57 | +0.55 |
| Martin ratioReturn relative to average drawdown | 6.54 | 4.05 | +2.49 |
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Drawdowns
SPMB vs. CMBS - Drawdown Comparison
The maximum SPMB drawdown since its inception was -18.03%, which is greater than CMBS's maximum drawdown of -15.87%. Use the drawdown chart below to compare losses from any high point for SPMB and CMBS.
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Drawdown Indicators
| SPMB | CMBS | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -18.03% | -15.87% | -2.16% |
Max Drawdown (1Y)Largest decline over 1 year | -2.89% | -2.44% | -0.45% |
Max Drawdown (3Y)Largest decline over 3 years | -7.66% | -3.29% | -4.37% |
Max Drawdown (5Y)Largest decline over 5 years | -17.49% | -15.87% | -1.62% |
Max Drawdown (10Y)Largest decline over 10 years | -18.03% | -15.87% | -2.16% |
Current DrawdownCurrent decline from peak | -0.79% | -1.40% | +0.61% |
Average DrawdownAverage peak-to-trough decline | -2.85% | -2.95% | +0.10% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 0.93% | 0.94% | -0.01% |
Volatility
SPMB vs. CMBS - Volatility Comparison
SPDR Portfolio Mortgage Backed Bond ETF (SPMB) and iShares CMBS ETF (CMBS) have volatilities of 1.28% and 1.26%, 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.
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Volatility by Period
| SPMB | CMBS | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 1.28% | 1.26% | +0.02% |
Volatility (6M)Calculated over the trailing 6-month period | 3.20% | 2.85% | +0.35% |
Volatility (1Y)Calculated over the trailing 1-year period | 4.25% | 3.66% | +0.59% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 6.79% | 5.32% | +1.47% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 7.61% | 5.76% | +1.85% |
SPMB vs. CMBS - Expense Ratio Comparison
SPMB has a 0.04% 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
SPMB vs. CMBS - Dividend Comparison
SPMB's dividend yield for the trailing twelve months is around 4.06%, more than CMBS's 3.57% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
CMBS iShares CMBS ETF | 3.57% | 3.45% | 3.31% | 2.97% | 2.65% | 2.46% | 2.83% | 2.74% | 2.70% | 2.50% | 2.29% | 2.31% |
SPMB SPDR Portfolio Mortgage Backed Bond ETF | 4.06% | 3.98% | 3.76% | 3.21% | 2.98% | 2.59% | 2.95% | 3.24% | 3.36% | 3.13% | 2.99% | 3.05% |
Frequently Asked Questions
SPMB and CMBS have a correlation of 0.37, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.
SPMB has higher volatility (1.28%) compared to CMBS (1.26%). In terms of maximum drawdown, SPMB dropped -18.03% vs CMBS's -15.87%.
On 10-year performance, CMBS leads with 2.04% vs 1.34% for SPMB. On fees, SPMB is cheaper at 0.04% per year. Their volatility is very similar. 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 2.04% return vs 1.34%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.
SPMB is cheaper with a 0.04% expense ratio, compared with 0.25% for CMBS.
SPMB has the higher dividend yield at 4.06%, compared with 3.57% for CMBS.
SPMB tracks Bloomberg US Aggregate Securitized - MBS, while CMBS tracks Barclays Capital U.S. CMBS (ERISA Only) Index. They also come from different issuers: State Street and iShares. Their fees differ too: 0.04% for SPMB and 0.25% for CMBS.
SPMB currently has the higher Sharpe Ratio (1.44 vs 1.04), 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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