VMFXX vs. SPAXX

Last updated Jun 13, 2026

VMFXX (Vanguard Federal Money Market Fund) and SPAXX (Fidelity Government Money Market Fund) are both Money Market funds. Over the past 5 years, VMFXX returned 2.39%/yr vs 1.45%/yr for SPAXX. Their correlation of 0.82 suggests significant overlap in exposure. VMFXX charges 0.11%/yr vs 0.42%/yr for SPAXX.

Performance

VMFXX vs. SPAXX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Federal Money Market Fund (VMFXX) and Fidelity Government Money Market Fund (SPAXX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, VMFXX achieves a 1.50% return, which is significantly higher than SPAXX's 1.37% return.

VMFXX

• 1D: 0.00%
• 1M: 0.30%
• YTD: 1.50%
• 6M: 1.82%
• 1Y: 3.95%
• 3Y*: 3.35%
• 5Y*: 2.39%
• 10Y*: —

SPAXX

• 1D: 0.00%
• 1M: 0.28%
• YTD: 1.37%
• 6M: 1.67%
• 1Y: 3.66%
• 3Y*: 2.42%
• 5Y*: 1.45%
• 10Y*: —

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

VMFXX vs. SPAXX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021
VMFXX Vanguard Federal Money Market Fund	1.50%	4.24%	1.64%	4.64%	0.00%	0.00%
SPAXX Fidelity Government Money Market Fund	1.37%	3.96%	1.54%	0.41%	0.00%	0.00%

Correlation

The correlation between VMFXX and SPAXX is 1.00 - these two move nearly in lockstep. At this level, holding both provides almost no diversification benefit. If you already own one, adding the other does little to reduce portfolio risk.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	1.00
Correlation (3Y) Calculated over the trailing 3-year period	0.89
Correlation (5Y) Calculated over the trailing 5-year period	0.82
Correlation (All Time) Calculated using the full available price history since May 25, 2021	0.82

The correlation between VMFXX and SPAXX shifts across timeframes, from 0.82 (5 years) to 1.00 (1 year), reflecting how their relationship changes across market environments.

Return for Risk

VMFXX vs. SPAXX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Federal Money Market Fund (VMFXX) and Fidelity Government Money Market Fund (SPAXX). 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.

Values are calculated on a 1-year rolling basis and updated daily. Risk-adjusted metrics are more stable over longer periods — use the period switch above to explore them.

	VMFXX	SPAXX	Difference
Sharpe ratio: Return per unit of total volatility	3.67	3.65	+0.03
Sortino ratio: Return per unit of downside risk	—	—	—
Omega ratio: Gain probability vs. loss probability	—	—	—
Calmar ratio: Return relative to maximum drawdown	—	—	—
Martin ratio: Return relative to average drawdown	—	—	—

VMFXX vs. SPAXX - Sharpe Ratio Comparison

The current VMFXX Sharpe Ratio is 3.67, which is comparable to the SPAXX Sharpe Ratio of 3.65. The chart below compares the historical Sharpe Ratios of VMFXX and SPAXX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Drawdowns

VMFXX vs. SPAXX - Drawdown Comparison

The maximum VMFXX drawdown since its inception was 0.00%, which is greater than SPAXX's maximum drawdown of 0.00%. Use the drawdown chart below to compare losses from any high point for VMFXX and SPAXX.

Drawdown Indicators

	VMFXX	SPAXX	Difference
Max Drawdown Largest peak-to-trough decline	0.00%	0.00%	0.00%
Max Drawdown (1Y) Largest decline over 1 year	0.00%	0.00%	0.00%
Max Drawdown (3Y) Largest decline over 3 years	0.00%	0.00%	0.00%
Max Drawdown (5Y) Largest decline over 5 years	0.00%	0.00%	0.00%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	0.00%	0.00%	0.00%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.00%	0.00%	0.00%

Volatility

VMFXX vs. SPAXX - Volatility Comparison

Vanguard Federal Money Market Fund (VMFXX) has a higher volatility of 0.30% compared to Fidelity Government Money Market Fund (SPAXX) at 0.28%. This indicates that VMFXX's price experiences larger fluctuations and is considered to be riskier than SPAXX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VMFXX	SPAXX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.30%	0.28%	+0.02%
Volatility (6M) Calculated over the trailing 6-month period	0.79%	0.66%	+0.13%
Volatility (1Y) Calculated over the trailing 1-year period	1.12%	1.03%	+0.09%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	0.94%	0.69%	+0.25%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	0.94%	0.69%	+0.25%

VMFXX vs. SPAXX - Expense Ratio Comparison

VMFXX has a 0.11% expense ratio, which is lower than SPAXX's 0.42% expense ratio.

Dividends

VMFXX vs. SPAXX - Dividend Comparison

VMFXX's dividend yield for the trailing twelve months is around 3.87%, more than SPAXX's 3.59% yield.

Position	TTM	2025	2024	2023
SPAXX Fidelity Government Money Market Fund	3.59%	3.88%	1.53%	0.41%
VMFXX Vanguard Federal Money Market Fund	3.87%	4.14%	1.63%	4.53%

Frequently Asked Questions

Can I hold both VMFXX and SPAXX in my portfolio?

With a correlation of 1.00, VMFXX and SPAXX move almost identically. Holding both adds very little diversification - you're essentially doubling your position in the same market segment. Choosing one is usually more capital-efficient.

Which is riskier, VMFXX or SPAXX?

VMFXX has higher volatility (0.30%) compared to SPAXX (0.28%). In terms of maximum drawdown, VMFXX dropped 0.00% vs SPAXX's 0.00%.

Which has better risk-adjusted returns?

VMFXX currently has the higher Sharpe Ratio (3.67 vs 3.65), 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.