MBB vs. SPMB
MBB (iShares MBS Bond ETF) and SPMB (SPDR Portfolio Mortgage Backed Bond ETF) are both Mortgage Backed Securities funds - MBB tracks the Barclays Capital U.S. MBS Index while SPMB tracks the Bloomberg US Aggregate Securitized - MBS. Both are passively managed. Over the past 10 years, MBB returned 1.34%/yr vs 1.34%/yr for SPMB. A 0.71 correlation means they provide meaningful diversification when combined. MBB charges 0.06%/yr vs 0.04%/yr for SPMB.
Performance
MBB vs. SPMB - Performance Comparison
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Returns By Period
In the year-to-date period, MBB achieves a 1.26% return, which is significantly lower than SPMB's 1.33% return. Over a longer period, both investments have demonstrated similar performance, with their 10-year annualized returns being quite close: MBB at 1.34% and SPMB at 1.34%.
MBB
- 1D
- 0.43%
- 1M
- 1.07%
- YTD
- 1.26%
- 6M
- 1.05%
- 1Y
- 5.71%
- 3Y*
- 4.50%
- 5Y*
- 0.54%
- 10Y*
- 1.34%
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%
MBB vs. SPMB - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
MBB iShares MBS Bond ETF | 1.26% | 8.38% | 1.31% | 5.01% | -11.74% | -1.43% | 4.08% | 6.18% | 0.82% | 2.49% |
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% |
Correlation
The correlation between MBB and SPMB is 0.96 - these two move nearly in lockstep. At this level, holding both provides almost no diversification benefit. If you already own one, adding the other does little to reduce portfolio risk.
| Correlation | |
|---|---|
Correlation (1Y) Calculated over the trailing 1-year period | 0.96 |
Correlation (3Y) Calculated over the trailing 3-year period | 0.97 |
Correlation (5Y) Calculated over the trailing 5-year period | 0.97 |
Correlation (10Y) Calculated over the trailing 10-year period | 0.86 |
Correlation (All Time) Calculated using the full available price history since Jan 30, 2009 | 0.71 |
Over the past year, MBB and SPMB have become more correlated (0.96) than their long-term average of 0.71, meaning their price movements have been converging.
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Return for Risk
MBB vs. SPMB — Risk / Return Rank
MBB
SPMB
MBB vs. SPMB - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for iShares MBS Bond ETF (MBB) and SPDR Portfolio Mortgage Backed Bond ETF (SPMB). 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.
| MBB | SPMB | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | -0.15 | ||
| Sortino ratioReturn per unit of downside risk | -0.28 | ||
| Omega ratioGain probability vs. loss probability | 1.23 | 1.26 | -0.03 |
| Calmar ratioReturn relative to maximum drawdown | 1.95 | 2.11 | -0.17 |
| Martin ratioReturn relative to average drawdown | 6.07 | 6.54 | -0.47 |
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Drawdowns
MBB vs. SPMB - Drawdown Comparison
The maximum MBB drawdown since its inception was -17.64%, roughly equal to the maximum SPMB drawdown of -18.03%. Use the drawdown chart below to compare losses from any high point for MBB and SPMB.
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Drawdown Indicators
| MBB | SPMB | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -17.64% | -18.03% | +0.39% |
Max Drawdown (1Y)Largest decline over 1 year | -2.94% | -2.89% | -0.05% |
Max Drawdown (3Y)Largest decline over 3 years | -7.68% | -7.66% | -0.02% |
Max Drawdown (5Y)Largest decline over 5 years | -17.19% | -17.49% | +0.30% |
Max Drawdown (10Y)Largest decline over 10 years | -17.64% | -18.03% | +0.39% |
Current DrawdownCurrent decline from peak | -0.85% | -0.79% | -0.06% |
Average DrawdownAverage peak-to-trough decline | -2.34% | -2.85% | +0.51% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 0.94% | 0.93% | +0.01% |
Volatility
MBB vs. SPMB - Volatility Comparison
iShares MBS Bond ETF (MBB) and SPDR Portfolio Mortgage Backed Bond ETF (SPMB) have volatilities of 1.32% and 1.28%, 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
| MBB | SPMB | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 1.32% | 1.28% | +0.04% |
Volatility (6M)Calculated over the trailing 6-month period | 3.34% | 3.20% | +0.14% |
Volatility (1Y)Calculated over the trailing 1-year period | 4.47% | 4.25% | +0.22% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 6.83% | 6.79% | +0.04% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 5.32% | 7.61% | -2.29% |
MBB vs. SPMB - Expense Ratio Comparison
MBB has a 0.06% expense ratio, which is higher than SPMB's 0.04% 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
MBB vs. SPMB - Dividend Comparison
MBB's dividend yield for the trailing twelve months is around 4.25%, more than SPMB's 4.06% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
MBB iShares MBS Bond ETF | 4.25% | 4.21% | 3.94% | 3.40% | 2.31% | 1.05% | 2.10% | 2.77% | 2.64% | 2.23% | 2.58% | 2.66% |
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
With a correlation of 0.96, MBB and SPMB 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.
MBB has higher volatility (1.32%) compared to SPMB (1.28%). In terms of maximum drawdown, MBB dropped -17.64% vs SPMB's -18.03%.
On 10-year performance, SPMB leads with 1.34% vs 1.34% for MBB. 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, SPMB has performed better with a 1.34% 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 0.06% for MBB.
MBB has the higher dividend yield at 4.25%, compared with 4.06% for SPMB.
MBB tracks Barclays Capital U.S. MBS Index, while SPMB tracks Bloomberg US Aggregate Securitized - MBS. They also come from different issuers: iShares and State Street. Their fees differ too: 0.06% for MBB and 0.04% for SPMB.
SPMB currently has the higher Sharpe Ratio (1.44 vs 1.29), 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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