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CMBS vs. SPAB
Performance
Return for Risk
Drawdowns
Volatility
Dividends

CMBS vs. SPAB

Last updated Jun 3, 2026

CMBS (iShares CMBS ETF) and SPAB (SPDR Portfolio Aggregate Bond ETF) are both exchange-traded funds - CMBS is a Mortgage Backed Securities fund tracking the Barclays Capital U.S. CMBS (ERISA Only) Index, while SPAB is a Total Bond Market fund tracking the Bloomberg U.S. Aggregate Bond Index. Both are passively managed. Over the past 10 years, CMBS returned 2.06%/yr vs 1.55%/yr for SPAB. A 0.52 correlation means they provide meaningful diversification when combined. CMBS charges 0.25%/yr vs 0.03%/yr for SPAB.

Performance

CMBS vs. SPAB - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in iShares CMBS ETF (CMBS) and SPDR Portfolio Aggregate Bond ETF (SPAB). The values are adjusted to include any dividend payments, if applicable.

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Returns By Period

In the year-to-date period, CMBS achieves a 0.18% return, which is significantly lower than SPAB's 0.41% return. Over the past 10 years, CMBS has outperformed SPAB with an annualized return of 2.06%, while SPAB has yielded a comparatively lower 1.55% annualized return.

CMBS

1D
-0.08%
1M
-0.19%
YTD
0.18%
6M
0.40%
1Y
4.38%
3Y*
5.16%
5Y*
0.79%
10Y*
2.06%

SPAB

1D
-0.04%
1M
0.11%
YTD
0.41%
6M
0.38%
1Y
5.28%
3Y*
3.97%
5Y*
0.17%
10Y*
1.55%
*Multi-year figures are annualized to reflect compound growth (CAGR)

CMBS vs. SPAB - Yearly Performance Comparison

2026 (YTD)202520242023202220212020201920182017
CMBS
iShares CMBS ETF		0.18%7.67%4.27%5.06%-11.21%-1.82%7.86%7.94%0.77%2.95%
SPAB
SPDR Portfolio Aggregate Bond ETF		0.41%7.25%1.25%5.56%-13.04%-1.77%7.39%8.67%-0.18%3.71%

Correlation

The correlation between CMBS and SPAB is 0.40, which is low. Their price movements are largely independent, making them effective diversification partners.

Correlation
Correlation (1Y)
Calculated over the trailing 1-year period

0.40

Correlation (3Y)
Calculated over the trailing 3-year period

0.57

Correlation (5Y)
Calculated over the trailing 5-year period

0.66

Correlation (10Y)
Calculated over the trailing 10-year period

0.57

Correlation (All Time)
Calculated using the full available price history since Feb 17, 2012

0.52

The correlation between CMBS and SPAB shifts across timeframes, from 0.40 (1 year) to 0.66 (5 years), reflecting how their relationship changes across market environments.

Compare stocks, funds, or ETFs

Search for stocks, ETFs, and funds for a quick comparison or use the comparison tool for more options.

iShares CMBS ETF

SPDR Portfolio Aggregate Bond ETF

Often compared with CMBS:
CMBS vs. SPLBCMBS vs. GBFCMBS vs. WCPNXCMBS vs. BNDCMBS vs. SCHZCMBS vs. TLTCMBS vs. VBTLX
Often compared with SPAB:
SPAB vs. BNDSPAB vs. SCHZSPAB vs. AGGSPAB vs. FBNDSPAB vs. VCLTSPAB vs. SCHPSPAB vs. VWINX

Return for Risk

CMBS vs. SPAB — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.
CMBS
CMBS Risk / Return Rank: 3333
Overall Rank
CMBS Sharpe Ratio Rank: 3333
Sharpe Ratio Rank
CMBS Sortino Ratio Rank: 3434
Sortino Ratio Rank
CMBS Omega Ratio Rank: 3131
Omega Ratio Rank
CMBS Calmar Ratio Rank: 3535
Calmar Ratio Rank
CMBS Martin Ratio Rank: 3232
Martin Ratio Rank
SPAB
SPAB Risk / Return Rank: 3838
Overall Rank
SPAB Sharpe Ratio Rank: 3838
Sharpe Ratio Rank
SPAB Sortino Ratio Rank: 4141
Sortino Ratio Rank
SPAB Omega Ratio Rank: 3838
Omega Ratio Rank
SPAB Calmar Ratio Rank: 3636
Calmar Ratio Rank
SPAB Martin Ratio Rank: 3535
Martin Ratio Rank
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.

CMBS vs. SPAB - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for iShares CMBS ETF (CMBS) and SPDR Portfolio Aggregate Bond ETF (SPAB). 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.

CMBSSPABDifference

Sharpe ratio

Return per unit of total volatility

1.19

1.41

-0.22

Sortino ratio

Return per unit of downside risk

1.81

2.13

-0.31

Omega ratio

Gain probability vs. loss probability

1.21

1.25

-0.04

Calmar ratio

Return relative to maximum drawdown

1.78

1.83

-0.05

Martin ratio

Return relative to average drawdown

5.01

5.49

-0.48

Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

CMBS vs. SPAB - Sharpe Ratio Comparison

The current CMBS Sharpe Ratio is 1.19, which is comparable to the SPAB Sharpe Ratio of 1.41. The chart below compares the historical Sharpe Ratios of CMBS and SPAB, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

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Sharpe Ratios by Period

CMBSSPABDifference

Sharpe Ratio (1Y)

Calculated over the trailing 1-year period

1.19

1.41

-0.22

Sharpe Ratio (5Y)

Calculated over the trailing 5-year period

0.15

0.03

+0.12

Sharpe Ratio (10Y)

Calculated over the trailing 10-year period

0.36

0.28

+0.08

Sharpe Ratio (All Time)

Calculated using the full available price history

0.43

0.51

-0.07

Drawdowns

CMBS vs. SPAB - Drawdown Comparison

The maximum CMBS drawdown since its inception was -15.87%, smaller than the maximum SPAB drawdown of -18.56%. Use the drawdown chart below to compare losses from any high point for CMBS and SPAB.

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Drawdown Indicators

CMBSSPABDifference

Max Drawdown

Largest peak-to-trough decline

-15.87%

-18.56%

+2.69%

Max Drawdown (1Y)

Largest decline over 1 year

-2.44%

-2.74%

+0.30%

Max Drawdown (3Y)

Largest decline over 3 years

-3.29%

-6.08%

+2.79%

Max Drawdown (5Y)

Largest decline over 5 years

-15.87%

-17.96%

+2.09%

Max Drawdown (10Y)

Largest decline over 10 years

-15.87%

-18.56%

+2.69%

Current Drawdown

Current decline from peak

-1.73%

-2.15%

+0.42%

Average Drawdown

Average peak-to-trough decline

-2.95%

-3.08%

+0.13%

Ulcer Index

Depth and duration of drawdowns from previous peaks

0.87%

0.91%

-0.04%

Volatility

CMBS vs. SPAB - Volatility Comparison

The current volatility for iShares CMBS ETF (CMBS) is 1.13%, while SPDR Portfolio Aggregate Bond ETF (SPAB) has a volatility of 1.19%. This indicates that CMBS experiences smaller price fluctuations and is considered to be less risky than SPAB based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

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Volatility by Period

CMBSSPABDifference

Volatility (1M)

Calculated over the trailing 1-month period

1.13%

1.19%

-0.06%

Volatility (6M)

Calculated over the trailing 6-month period

2.83%

2.61%

+0.22%

Volatility (1Y)

Calculated over the trailing 1-year period

3.71%

3.78%

-0.07%

Volatility (5Y)

Calculated over the trailing 5-year period, annualized

5.31%

5.92%

-0.61%

Volatility (10Y)

Calculated over the trailing 10-year period, annualized

5.77%

5.54%

+0.23%

CMBS vs. SPAB - Expense Ratio Comparison

CMBS has a 0.25% expense ratio, which is higher than SPAB's 0.03% 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

CMBS vs. SPAB - Dividend Comparison

CMBS's dividend yield for the trailing twelve months is around 3.58%, less than SPAB's 4.05% yield.

PositionTTM20252024202320222021202020192018201720162015
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%
SPAB
SPDR Portfolio Aggregate Bond ETF		4.05%3.97%3.86%3.34%2.59%2.11%2.43%2.92%2.96%2.67%2.63%2.59%

Frequently Asked Questions

CMBS and SPAB have a correlation of 0.40, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

SPAB has higher volatility (1.19%) compared to CMBS (1.13%). In terms of maximum drawdown, CMBS dropped -15.87% vs SPAB's -18.56%.

On 10-year performance, CMBS leads with 2.06% vs 1.55% for SPAB. On fees, SPAB is cheaper at 0.03% 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 2.06% return vs 1.55%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

SPAB is cheaper with a 0.03% expense ratio, compared with 0.25% for CMBS.

SPAB has the higher dividend yield at 4.05%, compared with 3.58% for CMBS.

CMBS is categorized as Mortgage Backed Securities, while SPAB is Total Bond Market. CMBS tracks Barclays Capital U.S. CMBS (ERISA Only) Index, while SPAB tracks Bloomberg U.S. Aggregate Bond Index. They also come from different issuers: iShares and State Street. Their fees differ too: 0.25% for CMBS and 0.03% for SPAB.

SPAB currently has the higher Sharpe Ratio (1.41 vs 1.19), 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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