GNMA vs. SPMB

Last updated Apr 1, 2026

Compare and contrast key facts about iShares GNMA Bond ETF (GNMA) and SPDR Portfolio Mortgage Backed Bond ETF (SPMB).

GNMA and SPMB are both exchange-traded funds (ETFs), meaning they are traded on stock exchanges and can be bought and sold throughout the day. GNMA is a passively managed fund by iShares that tracks the performance of the Barclays Capital GNMA Index. It was launched on Feb 14, 2012. 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. Both GNMA and SPMB 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

GNMA vs. SPMB - Performance Comparison

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

GNMA vs. SPMB - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
GNMA iShares GNMA Bond ETF	0.22%	8.25%	1.07%	5.34%	-10.83%	-1.86%	3.51%	5.85%	0.85%	1.74%
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%

Returns By Period

In the year-to-date period, GNMA achieves a 0.22% return, which is significantly lower than SPMB's 0.51% return. Both investments have delivered pretty close results over the past 10 years, with GNMA having a 1.24% annualized return and SPMB not far ahead at 1.29%.

GNMA

• 1D: 0.05%
• 1M: -1.75%
• YTD: 0.22%
• 6M: 2.07%
• 1Y: 5.33%
• 3Y*: 3.97%
• 5Y*: 0.40%
• 10Y*: 1.24%

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%

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

GNMA vs. SPMB - Expense Ratio Comparison

GNMA has a 0.15% 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%.

GNMA

iShares GNMA Bond ETF

SPMB

SPDR Portfolio Mortgage Backed Bond ETF

Return for Risk

GNMA vs. SPMB — Risk / Return Rank

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

GNMA

GNMA Risk / Return Rank: 63
GNMA Sharpe Ratio Rank: 64
GNMA Sortino Ratio Rank: 65
GNMA Omega Ratio Rank: 55
GNMA Calmar Ratio Rank: 73
GNMA Martin Ratio Rank: 58

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

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.

GNMA vs. SPMB - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for iShares GNMA Bond ETF (GNMA) 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.

	GNMA	SPMB	Difference
Sharpe ratio Return per unit of total volatility	1.12	1.18	-0.06
Sortino ratio Return per unit of downside risk	1.63	1.69	-0.06
Omega ratio Gain probability vs. loss probability	1.20	1.21	-0.01
Calmar ratio Return relative to maximum drawdown	1.88	2.01	-0.12
Martin ratio Return relative to average drawdown	5.60	5.76	-0.16
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

GNMA vs. SPMB - Sharpe Ratio Comparison

The current GNMA Sharpe Ratio is 1.12, which is comparable to the SPMB Sharpe Ratio of 1.18. The chart below compares the historical Sharpe Ratios of GNMA and SPMB, 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

	GNMA	SPMB	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.12	1.18	-0.06
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.06	0.05	+0.01
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.24	0.17	+0.07
Sharpe Ratio (All Time) Calculated using the full available price history	0.25	0.34	-0.09

Correlation

The correlation between GNMA and SPMB is 0.61, which is considered to be moderate. This suggests that the two assets have some degree of positive relationship in their price movements. Moderate correlation can be acceptable for portfolio diversification, offering a balance between risk and potential returns.

Dividends

GNMA vs. SPMB - Dividend Comparison

GNMA's dividend yield for the trailing twelve months is around 4.21%, more than SPMB's 4.02% yield.

	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
GNMA iShares GNMA Bond ETF	4.21%	4.19%	4.15%	3.43%	2.01%	0.64%	1.89%	2.61%	2.41%	2.15%	1.89%	1.50%
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%

Drawdowns

GNMA vs. SPMB - Drawdown Comparison

The maximum GNMA drawdown since its inception was -17.09%, smaller than the maximum SPMB drawdown of -18.03%. Use the drawdown chart below to compare losses from any high point for GNMA and SPMB.

Drawdown Indicators

	GNMA	SPMB	Difference
Max Drawdown Largest peak-to-trough decline	-17.09%	-18.03%	+0.94%
Max Drawdown (1Y) Largest decline over 1 year	-2.93%	-2.93%	0.00%
Max Drawdown (5Y) Largest decline over 5 years	-16.02%	-17.49%	+1.47%
Max Drawdown (10Y) Largest decline over 10 years	-17.09%	-18.03%	+0.94%
Current Drawdown Current decline from peak	-1.75%	-1.58%	-0.17%
Average Drawdown Average peak-to-trough decline	-3.69%	-2.87%	-0.82%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.98%	1.02%	-0.04%

Volatility

GNMA vs. SPMB - Volatility Comparison

iShares GNMA Bond ETF (GNMA) and SPDR Portfolio Mortgage Backed Bond ETF (SPMB) have volatilities of 1.77% and 1.83%, 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.

Volatility by Period

	GNMA	SPMB	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.77%	1.83%	-0.06%
Volatility (6M) Calculated over the trailing 6-month period	2.76%	2.77%	-0.01%
Volatility (1Y) Calculated over the trailing 1-year period	4.78%	4.88%	-0.10%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	6.56%	6.73%	-0.17%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	5.11%	7.59%	-2.48%