VFIRX vs. PRGMX

Last updated Jun 4, 2026

VFIRX (Vanguard Short-Term Treasury Fund Admiral Shares) and PRGMX (T. Rowe Price GNMA Fund) are both Government Bonds funds. Over the past 10 years, VFIRX returned 1.71%/yr vs 1.31%/yr for PRGMX. A 0.71 correlation means they provide meaningful diversification when combined. VFIRX charges 0.10%/yr vs 0.58%/yr for PRGMX.

Performance

VFIRX vs. PRGMX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Short-Term Treasury Fund Admiral Shares (VFIRX) 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, VFIRX achieves a 0.44% return, which is significantly lower than PRGMX's 0.93% return. Over the past 10 years, VFIRX has outperformed PRGMX with an annualized return of 1.71%, while PRGMX has yielded a comparatively lower 1.31% annualized return.

VFIRX

• 1D: -0.10%
• 1M: 0.12%
• YTD: 0.44%
• 6M: 0.65%
• 1Y: 3.58%
• 3Y*: 4.12%
• 5Y*: 1.51%
• 10Y*: 1.71%

PRGMX

• 1D: 0.00%
• 1M: 0.56%
• YTD: 0.93%
• 6M: 1.33%
• 1Y: 7.89%
• 3Y*: 4.84%
• 5Y*: 0.69%
• 10Y*: 1.31%

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

VFIRX vs. PRGMX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VFIRX Vanguard Short-Term Treasury Fund Admiral Shares	0.44%	5.47%	3.85%	3.66%	-4.61%	-0.80%	4.06%	3.71%	1.47%	0.40%
PRGMX T. Rowe Price GNMA Fund	0.93%	8.72%	1.86%	5.62%	-11.45%	-2.18%	4.21%	5.18%	0.58%	1.23%

Correlation

The correlation between VFIRX and PRGMX is 0.77, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.77
Correlation (3Y) Calculated over the trailing 3-year period	0.75
Correlation (5Y) Calculated over the trailing 5-year period	0.77
Correlation (10Y) Calculated over the trailing 10-year period	0.70
Correlation (All Time) Calculated using the full available price history since Feb 14, 2001	0.71

The correlation between VFIRX and PRGMX has been stable across timeframes, ranging from 0.70 to 0.77 - a consistent structural relationship.

Return for Risk

VFIRX vs. PRGMX — Risk / Return Rank

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

VFIRX

VFIRX Risk / Return Rank: 42
VFIRX Sharpe Ratio Rank: 34
VFIRX Sortino Ratio Rank: 49
VFIRX Omega Ratio Rank: 43
VFIRX Calmar Ratio Rank: 43
VFIRX Martin Ratio Rank: 39

PRGMX

PRGMX Risk / Return Rank: 44
PRGMX Sharpe Ratio Rank: 42
PRGMX Sortino Ratio Rank: 46
PRGMX Omega Ratio Rank: 43
PRGMX Calmar Ratio Rank: 48
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.

VFIRX vs. PRGMX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Short-Term Treasury Fund Admiral Shares (VFIRX) 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.

	VFIRX	PRGMX	Difference
Sharpe ratio: Return per unit of total volatility	1.68	1.89	-0.21
Sortino ratio: Return per unit of downside risk	2.94	2.86	+0.08
Omega ratio: Gain probability vs. loss probability	1.35	1.36	0.00
Calmar ratio: Return relative to maximum drawdown	2.49	2.64	-0.15
Martin ratio: Return relative to average drawdown	8.39	8.88	-0.49
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

VFIRX vs. PRGMX - Sharpe Ratio Comparison

The current VFIRX Sharpe Ratio is 1.68, which is comparable to the PRGMX Sharpe Ratio of 1.89. The chart below compares the historical Sharpe Ratios of VFIRX 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

	VFIRX	PRGMX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.68	1.89	-0.21
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.57	0.11	+0.46
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.81	0.28	+0.53
Sharpe Ratio (All Time) Calculated using the full available price history	1.16	0.93	+0.23

Drawdowns

VFIRX vs. PRGMX - Drawdown Comparison

The maximum VFIRX drawdown since its inception was -6.73%, smaller than the maximum PRGMX drawdown of -18.22%. Use the drawdown chart below to compare losses from any high point for VFIRX and PRGMX.

Drawdown Indicators

	VFIRX	PRGMX	Difference
Max Drawdown Largest peak-to-trough decline	-6.73%	-18.22%	+11.49%
Max Drawdown (1Y) Largest decline over 1 year	-1.40%	-3.00%	+1.60%
Max Drawdown (3Y) Largest decline over 3 years	-1.40%	-7.14%	+5.74%
Max Drawdown (5Y) Largest decline over 5 years	-6.73%	-17.30%	+10.57%
Max Drawdown (10Y) Largest decline over 10 years	-6.73%	-18.22%	+11.49%
Current Drawdown Current decline from peak	-0.56%	-1.25%	+0.69%
Average Drawdown Average peak-to-trough decline	-0.71%	-2.24%	+1.53%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.42%	0.89%	-0.47%

Volatility

VFIRX vs. PRGMX - Volatility Comparison

The current volatility for Vanguard Short-Term Treasury Fund Admiral Shares (VFIRX) is 0.61%, while T. Rowe Price GNMA Fund (PRGMX) has a volatility of 1.72%. This indicates that VFIRX 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

	VFIRX	PRGMX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.61%	1.72%	-1.11%
Volatility (6M) Calculated over the trailing 6-month period	1.50%	3.11%	-1.61%
Volatility (1Y) Calculated over the trailing 1-year period	2.08%	4.20%	-2.12%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	2.68%	6.38%	-3.70%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	2.12%	4.77%	-2.65%

VFIRX vs. PRGMX - Expense Ratio Comparison

VFIRX has a 0.10% expense ratio, which is lower than PRGMX's 0.58% expense ratio.

Dividends

VFIRX vs. PRGMX - Dividend Comparison

VFIRX's dividend yield for the trailing twelve months is around 3.85%, less than PRGMX's 4.99% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PRGMX T. Rowe Price GNMA Fund	4.99%	4.96%	4.47%	3.54%	1.38%	0.59%	1.44%	2.39%	2.78%	2.98%	2.88%	3.12%
VFIRX Vanguard Short-Term Treasury Fund Admiral Shares	3.85%	3.99%	4.49%	4.07%	2.03%	0.60%	2.30%	2.49%	2.21%	1.25%	1.28%	0.93%

Frequently Asked Questions

Can I hold both VFIRX and PRGMX in my portfolio?

VFIRX and PRGMX have a correlation of 0.77, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, VFIRX or PRGMX?

PRGMX has higher volatility (1.72%) compared to VFIRX (0.61%). In terms of maximum drawdown, VFIRX dropped -6.73% vs PRGMX's -18.22%.

Which has better risk-adjusted returns?

PRGMX currently has the higher Sharpe Ratio (1.89 vs 1.68), 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.