SPMB vs. IUSB

Last updated Apr 1, 2026

Compare and contrast key facts about SPDR Portfolio Mortgage Backed Bond ETF (SPMB) and iShares Core Universal USD Bond ETF (IUSB).

SPMB and IUSB are both exchange-traded funds (ETFs), meaning they are traded on stock exchanges and can be bought and sold throughout the day. SPMB is a passively managed fund by State Street that tracks the performance of the Bloomberg US Aggregate Securitized - MBS. It was launched on Jan 15, 2009. IUSB is a passively managed fund by iShares that tracks the performance of the Bloomberg U.S. Universal Index. It was launched on Jun 10, 2014. Both SPMB and IUSB are passive ETFs, meaning that they are not actively managed but aim to replicate the performance of the underlying index as closely as possible.

Performance

SPMB vs. IUSB - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in SPDR Portfolio Mortgage Backed Bond ETF (SPMB) and iShares Core Universal USD Bond ETF (IUSB). The values are adjusted to include any dividend payments, if applicable.

SPMB vs. IUSB - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
SPMB SPDR Portfolio Mortgage Backed Bond ETF	0.51%	8.29%	1.35%	5.09%	-12.05%	-1.46%	4.19%	6.16%	1.01%	2.13%
IUSB iShares Core Universal USD Bond ETF	-0.07%	7.38%	2.11%	6.23%	-13.04%	-1.33%	7.62%	9.13%	-0.27%	3.82%

Returns By Period

In the year-to-date period, SPMB achieves a 0.51% return, which is significantly higher than IUSB's -0.07% return. Over the past 10 years, SPMB has underperformed IUSB with an annualized return of 1.29%, while IUSB has yielded a comparatively higher 2.06% annualized return.

SPMB

• 1D: 0.31%
• 1M: -1.58%
• YTD: 0.51%
• 6M: 1.98%
• 1Y: 5.73%
• 3Y*: 4.11%
• 5Y*: 0.37%
• 10Y*: 1.29%

IUSB

• 1D: 0.20%
• 1M: -1.81%
• YTD: -0.07%
• 6M: 0.97%
• 1Y: 4.55%
• 3Y*: 4.07%
• 5Y*: 0.53%
• 10Y*: 2.06%

*Multi-year figures are annualized to reflect compound growth (CAGR)

SPMB vs. IUSB - Expense Ratio Comparison

SPMB has a 0.04% expense ratio, which is lower than IUSB's 0.06% 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%.

IUSB

iShares Core Universal USD Bond ETF

SPMB

SPDR Portfolio Mortgage Backed Bond ETF

Return for Risk

SPMB vs. IUSB — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.

SPMB

SPMB Risk / Return Rank: 66
SPMB Sharpe Ratio Rank: 68
SPMB Sortino Ratio Rank: 68
SPMB Omega Ratio Rank: 59
SPMB Calmar Ratio Rank: 77
SPMB Martin Ratio Rank: 60

IUSB

IUSB Risk / Return Rank: 66
IUSB Sharpe Ratio Rank: 66
IUSB Sortino Ratio Rank: 64
IUSB Omega Ratio Rank: 57
IUSB Calmar Ratio Rank: 77
IUSB Martin Ratio Rank: 64

The rank (0–100) shows how this investment's returns compare to the risk taken. Higher = better. Based on the past 12 months of data, combining Sharpe, Sortino, and other metrics used by quantitative funds and institutional investors.

SPMB vs. IUSB - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for SPDR Portfolio Mortgage Backed Bond ETF (SPMB) and iShares Core Universal USD Bond ETF (IUSB). 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.

	SPMB	IUSB	Difference
Sharpe ratio Return per unit of total volatility	1.18	1.11	+0.07
Sortino ratio Return per unit of downside risk	1.69	1.56	+0.13
Omega ratio Gain probability vs. loss probability	1.21	1.20	+0.02
Calmar ratio Return relative to maximum drawdown	2.01	1.92	+0.09
Martin ratio Return relative to average drawdown	5.76	5.96	-0.20
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

SPMB vs. IUSB - Sharpe Ratio Comparison

The current SPMB Sharpe Ratio is 1.18, which is comparable to the IUSB Sharpe Ratio of 1.11. The chart below compares the historical Sharpe Ratios of SPMB and IUSB, offering insights into how both investments have performed under varying market conditions. These values are calculated using daily returns over the previous 12 months.

Sharpe Ratios by Period

	SPMB	IUSB	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.18	1.11	+0.07
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.05	0.09	-0.04
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.17	0.41	-0.24
Sharpe Ratio (All Time) Calculated using the full available price history	0.34	0.46	-0.12

Correlation

The correlation between SPMB and IUSB is 0.73, which is considered to be high. That indicates a strong positive relationship between their price movements. Having highly-correlated positions in a portfolio may signal a lack of diversification, potentially leading to increased risk during market downturns.

Dividends

SPMB vs. IUSB - Dividend Comparison

SPMB's dividend yield for the trailing twelve months is around 4.02%, less than IUSB's 4.23% yield.

	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
SPMB SPDR Portfolio Mortgage Backed Bond ETF	4.02%	3.98%	3.76%	3.21%	2.98%	2.59%	2.95%	3.24%	3.36%	3.13%	2.99%	3.05%
IUSB iShares Core Universal USD Bond ETF	4.23%	4.17%	4.04%	3.46%	2.53%	1.74%	2.68%	3.04%	2.98%	2.56%	2.60%	1.95%

Drawdowns

SPMB vs. IUSB - Drawdown Comparison

The maximum SPMB drawdown since its inception was -18.03%, roughly equal to the maximum IUSB drawdown of -17.90%. Use the drawdown chart below to compare losses from any high point for SPMB and IUSB.

Drawdown Indicators

	SPMB	IUSB	Difference
Max Drawdown Largest peak-to-trough decline	-18.03%	-17.90%	-0.13%
Max Drawdown (1Y) Largest decline over 1 year	-2.93%	-2.49%	-0.44%
Max Drawdown (5Y) Largest decline over 5 years	-17.49%	-17.87%	+0.38%
Max Drawdown (10Y) Largest decline over 10 years	-18.03%	-17.90%	-0.13%
Current Drawdown Current decline from peak	-1.58%	-1.81%	+0.23%
Average Drawdown Average peak-to-trough decline	-2.87%	-3.62%	+0.75%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.02%	0.80%	+0.22%

Volatility

SPMB vs. IUSB - Volatility Comparison

SPDR Portfolio Mortgage Backed Bond ETF (SPMB) has a higher volatility of 1.83% compared to iShares Core Universal USD Bond ETF (IUSB) at 1.62%. This indicates that SPMB's price experiences larger fluctuations and is considered to be riskier than IUSB based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	SPMB	IUSB	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.83%	1.62%	+0.21%
Volatility (6M) Calculated over the trailing 6-month period	2.77%	2.41%	+0.36%
Volatility (1Y) Calculated over the trailing 1-year period	4.88%	4.13%	+0.75%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	6.73%	5.77%	+0.96%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	7.59%	5.03%	+2.56%