GMMF vs. PMMF

Last updated Jul 22, 2026

GMMF (iShares Government Money Market ETF) and PMMF (iShares Prime Money Market ETF) are both Money Market funds. Both are actively managed. Over the past year, GMMF returned 3.75% vs 3.90% for PMMF. At a 0.47 correlation, their price movements are largely independent. Both charge a 0.20% expense ratio.

Performance

GMMF vs. PMMF - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in iShares Government Money Market ETF (GMMF) and iShares Prime Money Market ETF (PMMF). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both investments are quite close, with GMMF having a 1.92% return and PMMF slightly higher at 1.99%.

GMMF

• 1D: 0.01%
• 1M: 0.30%
• 6M: 1.73%
• YTD: 1.92%
• 1Y: 3.75%
• 3Y*: —
• 5Y*: —
• 10Y*: —
• ALL TIME*: 3.88%

PMMF

• 1D: -0.01%
• 1M: 0.31%
• 6M: 1.80%
• YTD: 1.99%
• 1Y: 3.90%
• 3Y*: —
• 5Y*: —
• 10Y*: —
• ALL TIME*: 3.97%

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

Liquidity Comparison

Position	Avg. Volume Value (2W)	Avg. Volume Value (1M)	Avg. Volume Value (3M)
GMMF iShares Government Money Market ETF	$1.99M	$2.53M	$3.36M

GMMF vs. PMMF - Yearly Performance Comparison

	2026 (YTD)	2025
GMMF iShares Government Money Market ETF	1.92%	3.70%
PMMF iShares Prime Money Market ETF	1.99%	3.75%

Correlation

The correlation between GMMF and PMMF is 0.53, 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	0.53
Correlation (All Time) Calculated using the full available price history since Feb 6, 2025	0.47

The correlation between GMMF and PMMF has been stable across timeframes, ranging from 0.47 to 0.53 - a consistent structural relationship.

Return for Risk

GMMF vs. PMMF — Risk / Return Rank

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

GMMF

GMMF Risk / Return Rank: 100
GMMF Sharpe Ratio Rank: 100
GMMF Sortino Ratio Rank: 100
GMMF Omega Ratio Rank: 100
GMMF Calmar Ratio Rank: 100
GMMF Martin Ratio Rank: 100

PMMF

PMMF Risk / Return Rank: 100
PMMF Sharpe Ratio Rank: 100
PMMF Sortino Ratio Rank: 100
PMMF Omega Ratio Rank: 100
PMMF Calmar Ratio Rank: 100
PMMF Martin Ratio Rank: 100

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.

GMMF vs. PMMF - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for iShares Government Money Market ETF (GMMF) and iShares Prime Money Market ETF (PMMF). 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.

	GMMF	PMMF	Difference
Sharpe ratio: Return per unit of total volatility	18.86	20.47	-1.61
Sortino ratio: Return per unit of downside risk	139.34	99.44	+39.90
Omega ratio: Gain probability vs. loss probability	40.52	42.59	-2.06
Calmar ratio: Return relative to maximum drawdown	251.61	157.15	+94.46
Martin ratio: Return relative to average drawdown	2,214.08	1,680.69	+533.39

GMMF vs. PMMF - Sharpe Ratio Comparison

The current GMMF Sharpe Ratio is 18.86, which is comparable to the PMMF Sharpe Ratio of 20.47. The chart below compares the historical Sharpe Ratios of GMMF and PMMF, 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

GMMF vs. PMMF - Drawdown Comparison

The maximum GMMF drawdown since its inception was -0.03%, smaller than the maximum PMMF drawdown of -0.13%. Use the drawdown chart below to compare losses from any high point for GMMF and PMMF.

Drawdown Indicators

	GMMF	PMMF	Difference
Max Drawdown Largest peak-to-trough decline	-0.03%	-0.13%	+0.10%
Max Drawdown (1Y) Largest decline over 1 year	-0.01%	-0.02%	+0.01%
Current Drawdown Current decline from peak	0.00%	-0.01%	+0.01%
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

GMMF vs. PMMF - Volatility Comparison

iShares Government Money Market ETF (GMMF) and iShares Prime Money Market ETF (PMMF) have volatilities of 0.05% and 0.05%, 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

	GMMF	PMMF	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.05%	0.05%	0.00%
Volatility (6M) Calculated over the trailing 6-month period	0.13%	0.13%	0.00%
Volatility (1Y) Calculated over the trailing 1-year period	0.20%	0.19%	+0.01%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	0.24%	0.34%	-0.10%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	0.24%	0.34%	-0.10%

GMMF vs. PMMF - Expense Ratio Comparison

Both GMMF and PMMF have an expense ratio of 0.20%, making them cost-effective options compared to the broader market, where average expense ratios typically range from 0.3% to 0.9%.

Dividends

GMMF vs. PMMF - Dividend Comparison

GMMF's dividend yield for the trailing twelve months is around 3.72%, less than PMMF's 3.92% yield.

Position	TTM	2025
GMMF iShares Government Money Market ETF	3.72%	3.45%
PMMF iShares Prime Money Market ETF	3.92%	3.59%

Frequently Asked Questions

Can I hold both GMMF and PMMF in my portfolio?

GMMF and PMMF have a correlation of 0.53, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, GMMF or PMMF?

PMMF has higher volatility (0.05%) compared to GMMF (0.05%). In terms of maximum drawdown, GMMF dropped -0.03% vs PMMF's -0.13%.

Which ETF is better, GMMF or PMMF?

On 1-year performance, PMMF leads with 3.90% vs 3.75% for GMMF. Both ETFs have the same 0.20% expense ratio. Their volatility is very similar. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF has performed better, GMMF or PMMF?

Over the 1-year period, PMMF has performed better with a 3.90% return vs 3.75%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

Which ETF is cheaper, GMMF or PMMF?

GMMF and PMMF have the same expense ratio: 0.20% per year.

Which ETF pays a higher dividend yield, GMMF or PMMF?

PMMF has the higher dividend yield at 3.92%, compared with 3.72% for GMMF.

What is the main difference between GMMF and PMMF?

They also come from different issuers: iShares and BlackRock.

Which has better risk-adjusted returns?

PMMF currently has the higher Sharpe Ratio (20.47 vs 18.86), 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.