VMBS vs. GNMA

Last updated Jun 3, 2026

VMBS (Vanguard Mortgage-Backed Securities ETF) and GNMA (iShares GNMA Bond ETF) are both Mortgage Backed Securities funds - VMBS tracks the Barclays Capital U.S. MBS Index while GNMA tracks the Barclays Capital GNMA Index. Both are passively managed. Over the past 10 years, VMBS returned 1.36%/yr vs 1.25%/yr for GNMA. A 0.67 correlation means they provide meaningful diversification when combined. VMBS charges 0.04%/yr vs 0.15%/yr for GNMA.

Performance

VMBS vs. GNMA - Performance Comparison

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

Returns By Period

In the year-to-date period, VMBS achieves a 0.81% return, which is significantly higher than GNMA's 0.75% return. Over the past 10 years, VMBS has outperformed GNMA with an annualized return of 1.36%, while GNMA has yielded a comparatively lower 1.25% annualized return.

VMBS

• 1D: -0.15%
• 1M: 0.05%
• YTD: 0.81%
• 6M: 1.13%
• 1Y: 6.98%
• 3Y*: 4.65%
• 5Y*: 0.53%
• 10Y*: 1.36%

GNMA

• 1D: 0.07%
• 1M: -0.07%
• YTD: 0.75%
• 6M: 1.24%
• 1Y: 6.63%
• 3Y*: 4.27%
• 5Y*: 0.61%
• 10Y*: 1.25%

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

VMBS vs. GNMA - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VMBS Vanguard Mortgage-Backed Securities ETF	0.81%	8.36%	1.70%	5.34%	-11.90%	-1.28%	3.76%	6.19%	0.91%	2.47%
GNMA iShares GNMA Bond ETF	0.75%	8.25%	1.07%	5.34%	-10.83%	-1.86%	3.51%	5.85%	0.85%	1.74%

Correlation

The correlation between VMBS and GNMA is 0.82, indicating a strong positive relationship between their price movements. Combining them offers limited diversification - they tend to fall together during downturns.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.82
Correlation (3Y) Calculated over the trailing 3-year period	0.91
Correlation (5Y) Calculated over the trailing 5-year period	0.92
Correlation (10Y) Calculated over the trailing 10-year period	0.79
Correlation (All Time) Calculated using the full available price history since Feb 22, 2012	0.67

The correlation between VMBS and GNMA shifts across timeframes, from 0.67 (all time) to 0.92 (5 years), reflecting how their relationship changes across market environments.

Return for Risk

VMBS vs. GNMA — Risk / Return Rank

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

VMBS

VMBS Risk / Return Rank: 48
VMBS Sharpe Ratio Rank: 46
VMBS Sortino Ratio Rank: 48
VMBS Omega Ratio Rank: 46
VMBS Calmar Ratio Rank: 49
VMBS Martin Ratio Rank: 50

GNMA

GNMA Risk / Return Rank: 46
GNMA Sharpe Ratio Rank: 44
GNMA Sortino Ratio Rank: 48
GNMA Omega Ratio Rank: 43
GNMA Calmar Ratio Rank: 49
GNMA Martin Ratio Rank: 47

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.

VMBS vs. GNMA - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Mortgage-Backed Securities ETF (VMBS) and iShares GNMA Bond ETF (GNMA). 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.

	VMBS	GNMA	Difference
Sharpe ratio Return per unit of total volatility	1.60	1.55	+0.05
Sortino ratio Return per unit of downside risk	2.39	2.38	+0.01
Omega ratio Gain probability vs. loss probability	1.29	1.28	+0.01
Calmar ratio Return relative to maximum drawdown	2.49	2.46	+0.04
Martin ratio Return relative to average drawdown	8.42	7.90	+0.51
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

VMBS vs. GNMA - Sharpe Ratio Comparison

The current VMBS Sharpe Ratio is 1.60, which is comparable to the GNMA Sharpe Ratio of 1.55. The chart below compares the historical Sharpe Ratios of VMBS and GNMA, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Sharpe Ratios by Period

	VMBS	GNMA	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.60	1.55	+0.05
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.08	0.09	-0.01
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.25	0.24	+0.01
Sharpe Ratio (All Time) Calculated using the full available price history	0.46	0.25	+0.21

Drawdowns

VMBS vs. GNMA - Drawdown Comparison

The maximum VMBS drawdown since its inception was -17.47%, roughly equal to the maximum GNMA drawdown of -17.09%. Use the drawdown chart below to compare losses from any high point for VMBS and GNMA.

Drawdown Indicators

	VMBS	GNMA	Difference
Max Drawdown Largest peak-to-trough decline	-17.47%	-17.09%	-0.38%
Max Drawdown (1Y) Largest decline over 1 year	-2.68%	-2.61%	-0.07%
Max Drawdown (3Y) Largest decline over 3 years	-7.65%	-7.13%	-0.52%
Max Drawdown (5Y) Largest decline over 5 years	-17.12%	-15.83%	-1.29%
Max Drawdown (10Y) Largest decline over 10 years	-17.47%	-17.09%	-0.38%
Current Drawdown Current decline from peak	-1.18%	-1.22%	+0.04%
Average Drawdown Average peak-to-trough decline	-2.50%	-3.66%	+1.16%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.80%	0.81%	-0.01%

Volatility

VMBS vs. GNMA - Volatility Comparison

Vanguard Mortgage-Backed Securities ETF (VMBS) has a higher volatility of 1.67% compared to iShares GNMA Bond ETF (GNMA) at 1.54%. This indicates that VMBS's price experiences larger fluctuations and is considered to be riskier than GNMA based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VMBS	GNMA	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.67%	1.54%	+0.13%
Volatility (6M) Calculated over the trailing 6-month period	3.18%	3.15%	+0.03%
Volatility (1Y) Calculated over the trailing 1-year period	4.37%	4.30%	+0.07%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	6.77%	6.61%	+0.16%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	5.40%	5.13%	+0.27%

VMBS vs. GNMA - Expense Ratio Comparison

VMBS has a 0.04% expense ratio, which is lower than GNMA's 0.15% 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%.

Dividends

VMBS vs. GNMA - Dividend Comparison

VMBS's dividend yield for the trailing twelve months is around 4.18%, less than GNMA's 4.23% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
GNMA iShares GNMA Bond ETF	4.23%	4.19%	4.15%	3.43%	2.01%	0.64%	1.89%	2.61%	2.41%	2.15%	1.89%	1.50%
VMBS Vanguard Mortgage-Backed Securities ETF	4.18%	4.20%	3.94%	3.31%	2.35%	1.02%	2.01%	2.77%	2.72%	2.16%	2.10%	2.12%

Frequently Asked Questions

Can I hold both VMBS and GNMA in my portfolio?

VMBS and GNMA have a correlation of 0.82, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, VMBS or GNMA?

VMBS has higher volatility (1.67%) compared to GNMA (1.54%). In terms of maximum drawdown, VMBS dropped -17.47% vs GNMA's -17.09%.

Which ETF is better, VMBS or GNMA?

On 10-year performance, VMBS leads with 1.36% vs 1.25% for GNMA. On fees, VMBS is cheaper at 0.04% per year. On volatility, GNMA has been the lower-risk option at 1.54%. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF has performed better, VMBS or GNMA?

Over the 10-year period, VMBS has performed better with a 1.36% return vs 1.25%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

Which ETF is cheaper, VMBS or GNMA?

VMBS is cheaper with a 0.04% expense ratio, compared with 0.15% for GNMA.

Which ETF pays a higher dividend yield, VMBS or GNMA?

GNMA has the higher dividend yield at 4.23%, compared with 4.18% for VMBS.

What is the main difference between VMBS and GNMA?

VMBS tracks Barclays Capital U.S. MBS Index, while GNMA tracks Barclays Capital GNMA Index. They also come from different issuers: Vanguard and iShares. Their fees differ too: 0.04% for VMBS and 0.15% for GNMA.

Which has better risk-adjusted returns?

VMBS currently has the higher Sharpe Ratio (1.60 vs 1.55), 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.