SPMB ETF: What Is It? A Complete Guide to Returns, Fees, Holdings and Alternative ETFs
Trading under the ticker SPMB, this SPDR Portfolio Mortgage Backed Bond ETF invests broadly in US government agency mortgage-backed securities (MBS). Its strengths are a low fee and steady monthly interest income, while interest rate sensitivity and prepayment risk are the key factors in any investment decision.
SubscribeWhat Is the SPDR Portfolio Mortgage Backed Bond ETF?
This bond ETF holds a broad range of mortgage-backed securities (MBS) guaranteed by US government agencies (Fannie Mae, Freddie Mac and Ginnie Mae) and tracks the Bloomberg MBS Index.
It suits bond investors who want somewhat higher interest income than Treasuries while keeping credit risk low.
It is a passive (index-tracking) ETF managed by State Street.
How Does the SPDR Portfolio Mortgage Backed Bond ETF Invest?
| Item | Details |
|---|---|
| Tracked Index | Bloomberg US MBS Index |
| Management Style | Passive (sampled index tracking) |
| Rebalancing Frequency | Monthly |
| Distribution Frequency | Monthly |
| Expense Ratio | 0.04% |
The fund holds a broad range of government agency guaranteed mortgage pass-through securities to track the performance of the Bloomberg MBS Index. Rather than selecting individual securities, it builds its portfolio by sampling to match index weightings, and it rebalances regularly as the index changes.
- Low credit risk, centered on agency-guaranteed MBS
- Low-cost passive management
SPDR Portfolio Mortgage Backed Bond ETF Size and Costs (AUM and Management Fee)
Assets under management (AUM) stand at $7.0B, and the Expense Ratio is 0.04% per year.
Compared with MBB and VMBS in the same MBS category, there are differences in fees and liquidity, and the strategic approach is distinct from that of JMBS and JMTG, which use active management.
SPDR Portfolio Mortgage Backed Bond ETF Performance and Trends
1-Year Price Performance
Dividend & Yield
52-Week Price RangeThe fund has shown price volatility as the interest rate environment has shifted. Relative performance has diverged depending on whether spreads over Treasuries are tightening or widening, and changes in prepayment speeds have also affected results.
Amid demand for bond allocations that seek stable interest income, fund flows have continued into the ETF as a core bond portfolio holding, in an environment that reacts sensitively to changes in interest rate policy.
SPDR Portfolio Mortgage Backed Bond ETF Pros and Cons
Its strengths are low credit risk thanks to agency guarantees and relatively high interest income, while interest rate and prepayment risks are its weaknesses.
💪 Key Strengths
⚠️ Points to Watch
Alternative ETFs and Related Products to the SPDR Portfolio Mortgage Backed Bond ETF
The main points of comparison are the differences in fees and liquidity versus MBB and VMBS shown in the table, and the strategic approach differs from that of JMBS and JMTG, which use active management. Investors who want to diversify beyond mortgage bonds into the broader bond market can also consider broad bond ETFs such as AGG and BND, which cover the entire US aggregate bond market.
Peer Comparison ETFs| Ticker | Name | Price | Change | AUM | Total Expense Ratio | Dividend Yield | 1Y |
|---|---|---|---|---|---|---|---|
 MBB | iShares MBS ETF | $91.41 | -0.1% | $35.6B | 0.04% | 4.45% | -5.0% |
 VMBS | Vanguard Mortgage-Backed Securities ETF | $45.25 | -0.2% | $16.0B | 0.03% | 4.35% | -4.6% |
 JMTG | JPMorgan Mortgage-Backed Securities ETF | $49.09 | -0.2% | $6.7B | 0.24% | 4.49% | -4.8% |
 LMBS | First Trust Low Duration Opportunities ETF | $48.77 | -0.1% | $6.5B | 0.66% | 4.18% | -2.5% |
 SMBS | Schwab Mortgage-Backed Securities ETF | $24.48 | -0.2% | $6.4B | 0.03% | 5.34% | -5.7% |
Top Holdings| Ticker | Name | Weight | Price | Change | Market Cap | P/E | Dividend Yield |
|---|---|---|---|---|---|---|---|
 MYMK | State Street My2031 Municipal Bond ETF | 0.07% | $24.63 | +0.0% | $0.0M | - | 2.61% |
SPDR Portfolio Mortgage Backed Bond ETF Investor Checkpoints
Here are the points to review before investing in SPMB. Because the fund holds agency-guaranteed bonds, credit risk is low, but you should check in advance how interest income may vary with interest rate changes and prepayment risk.
| Checkpoint | What to Check | Current Status |
|---|---|---|
| 💰 Expense Ratio | Check cumulative costs over a long holding period | In line with passive management |
| 📉 Interest Rate Sensitivity | Check price changes in response to rate moves | Exposed to bond duration |
| 🏠 Prepayment Risk | Check the trend in mortgage prepayments | Potential for fluctuation remains |
| 💱 Exchange Rate | Check the impact on returns converted into won | No currency hedging |
Interest rate changes and prepayment risk are the main drivers of return volatility. Agency guarantees keep credit risk low, but valuation losses can occur when interest rates rise.
It is a core bond holding suited to investors who want to diversify across government agency guaranteed mortgage bonds at a low fee. For active management, consider JMBS and JMTG, and for broad bond diversification, AGG and BND are also worth considering.
SubscribeDisclaimer: This content is for informational purposes only and does not constitute investment advice. All investment responsibility lies with the investor.
This article reflects information as of July 1, 2026.
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