VIIGX vs. PRGMX

Last updated Jun 5, 2026

VIIGX (Vanguard Intermediate-Term Treasury Index Fund Institutional Shares) and PRGMX (T. Rowe Price GNMA Fund) are both Government Bonds funds. Over the past 10 years, VIIGX returned 1.28%/yr vs 1.28%/yr for PRGMX. A 0.76 correlation means they provide meaningful diversification when combined. VIIGX charges 0.05%/yr vs 0.58%/yr for PRGMX.

Performance

VIIGX vs. PRGMX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Intermediate-Term Treasury Index Fund Institutional Shares (VIIGX) and T. Rowe Price GNMA Fund (PRGMX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, VIIGX achieves a -0.43% return, which is significantly lower than PRGMX's 0.69% return. Over a longer period, both investments have demonstrated similar performance, with their 10-year annualized returns being quite close: VIIGX at 1.28% and PRGMX at 1.28%.

VIIGX

• 1D: -0.16%
• 1M: -0.20%
• YTD: -0.43%
• 6M: -0.34%
• 1Y: 3.07%
• 3Y*: 3.53%
• 5Y*: 0.10%
• 10Y*: 1.28%

PRGMX

• 1D: -0.24%
• 1M: 0.07%
• YTD: 0.69%
• 6M: 1.32%
• 1Y: 6.95%
• 3Y*: 4.75%
• 5Y*: 0.62%
• 10Y*: 1.28%

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

VIIGX vs. PRGMX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VIIGX Vanguard Intermediate-Term Treasury Index Fund Institutional Shares	-0.43%	7.38%	1.62%	4.39%	-10.65%	-2.38%	7.65%	6.32%	1.36%	1.60%
PRGMX T. Rowe Price GNMA Fund	0.69%	8.72%	1.86%	5.62%	-11.45%	-2.18%	4.21%	5.18%	0.58%	1.23%

Correlation

The correlation between VIIGX and PRGMX is 0.86, 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	0.86
Correlation (3Y) Calculated over the trailing 3-year period	0.89
Correlation (5Y) Calculated over the trailing 5-year period	0.88
Correlation (10Y) Calculated over the trailing 10-year period	0.79
Correlation (All Time) Calculated using the full available price history since Nov 24, 2009	0.76

The correlation between VIIGX and PRGMX shifts across timeframes, from 0.76 (all time) to 0.89 (3 years), reflecting how their relationship changes across market environments.

Return for Risk

VIIGX vs. PRGMX — Risk / Return Rank

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

VIIGX

VIIGX Risk / Return Rank: 14
VIIGX Sharpe Ratio Rank: 15
VIIGX Sortino Ratio Rank: 15
VIIGX Omega Ratio Rank: 14
VIIGX Calmar Ratio Rank: 15
VIIGX Martin Ratio Rank: 14

PRGMX

PRGMX Risk / Return Rank: 43
PRGMX Sharpe Ratio Rank: 40
PRGMX Sortino Ratio Rank: 45
PRGMX Omega Ratio Rank: 42
PRGMX Calmar Ratio Rank: 46
PRGMX Martin Ratio Rank: 41

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.

VIIGX vs. PRGMX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Intermediate-Term Treasury Index Fund Institutional Shares (VIIGX) and T. Rowe Price GNMA Fund (PRGMX). 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.

	VIIGX	PRGMX	Difference
Sharpe ratio: Return per unit of total volatility	1.05	1.82	-0.77
Sortino ratio: Return per unit of downside risk	1.58	2.76	-1.18
Omega ratio: Gain probability vs. loss probability	1.19	1.34	-0.15
Calmar ratio: Return relative to maximum drawdown	1.27	2.56	-1.29
Martin ratio: Return relative to average drawdown	3.81	8.54	-4.73
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

VIIGX vs. PRGMX - Sharpe Ratio Comparison

The current VIIGX Sharpe Ratio is 1.05, which is lower than the PRGMX Sharpe Ratio of 1.82. The chart below compares the historical Sharpe Ratios of VIIGX and PRGMX, 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

	VIIGX	PRGMX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.05	1.82	-0.77
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.02	0.10	-0.08
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.29	0.27	+0.02
Sharpe Ratio (All Time) Calculated using the full available price history	0.49	0.93	-0.44

Drawdowns

VIIGX vs. PRGMX - Drawdown Comparison

The maximum VIIGX drawdown since its inception was -15.96%, smaller than the maximum PRGMX drawdown of -18.22%. Use the drawdown chart below to compare losses from any high point for VIIGX and PRGMX.

Drawdown Indicators

	VIIGX	PRGMX	Difference
Max Drawdown Largest peak-to-trough decline	-15.96%	-18.22%	+2.26%
Max Drawdown (1Y) Largest decline over 1 year	-2.83%	-3.00%	+0.17%
Max Drawdown (3Y) Largest decline over 3 years	-4.27%	-7.14%	+2.87%
Max Drawdown (5Y) Largest decline over 5 years	-15.09%	-17.30%	+2.21%
Max Drawdown (10Y) Largest decline over 10 years	-15.96%	-18.22%	+2.26%
Current Drawdown Current decline from peak	-2.03%	-1.49%	-0.54%
Average Drawdown Average peak-to-trough decline	-3.42%	-2.24%	-1.18%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.94%	0.89%	+0.05%

Volatility

VIIGX vs. PRGMX - Volatility Comparison

The current volatility for Vanguard Intermediate-Term Treasury Index Fund Institutional Shares (VIIGX) is 1.07%, while T. Rowe Price GNMA Fund (PRGMX) has a volatility of 1.66%. This indicates that VIIGX experiences smaller price fluctuations and is considered to be less risky than PRGMX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VIIGX	PRGMX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.07%	1.66%	-0.59%
Volatility (6M) Calculated over the trailing 6-month period	2.39%	3.10%	-0.71%
Volatility (1Y) Calculated over the trailing 1-year period	3.42%	4.20%	-0.78%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	5.34%	6.38%	-1.04%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.45%	4.77%	-0.32%

VIIGX vs. PRGMX - Expense Ratio Comparison

VIIGX has a 0.05% expense ratio, which is lower than PRGMX's 0.58% expense ratio.

Dividends

VIIGX vs. PRGMX - Dividend Comparison

VIIGX's dividend yield for the trailing twelve months is around 3.86%, less than PRGMX's 5.00% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PRGMX T. Rowe Price GNMA Fund	5.00%	4.96%	4.47%	3.54%	1.38%	0.59%	1.44%	2.39%	2.78%	2.98%	2.88%	3.12%
VIIGX Vanguard Intermediate-Term Treasury Index Fund Institutional Shares	3.86%	3.78%	3.97%	2.71%	1.73%	1.91%	2.23%	2.23%	2.07%	1.68%	1.64%	1.72%

Frequently Asked Questions

Can I hold both VIIGX and PRGMX in my portfolio?

VIIGX and PRGMX have a correlation of 0.86, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, VIIGX or PRGMX?

PRGMX has higher volatility (1.66%) compared to VIIGX (1.07%). In terms of maximum drawdown, VIIGX dropped -15.96% vs PRGMX's -18.22%.

Which has better risk-adjusted returns?

PRGMX currently has the higher Sharpe Ratio (1.82 vs 1.05), 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.