MMK vs. GMMF

Last updated Jul 24, 2026

MMK (State Street Prime Money Market ETF) and GMMF (iShares Government Money Market ETF) are both Money Market funds. Both are actively managed. At a 0.20 correlation, their price movements are largely independent. MMK charges 0.18%/yr vs 0.20%/yr for GMMF.

Performance

MMK vs. GMMF - Performance Comparison

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

Returns By Period

MMK

• 1D: 0.00%
• 1M: 0.31%
• 6M: —
• YTD: —
• 1Y: —
• 3Y*: —
• 5Y*: —
• 10Y*: —
• ALL TIME*: —

GMMF

• 1D: 0.00%
• 1M: 0.28%
• 6M: 1.73%
• YTD: 1.93%
• 1Y: 3.74%
• 3Y*: —
• 5Y*: —
• 10Y*: —
• ALL TIME*: 3.88%

*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	$1.96M	$2.30M	$3.32M
MMK State Street Prime Money Market ETF	$153.90K	$186.00K	$185.90K

MMK vs. GMMF - Yearly Performance Comparison

	2026 (YTD)
MMK State Street Prime Money Market ETF	1.59%
GMMF iShares Government Money Market ETF	1.53%

Correlation

The correlation between MMK and GMMF is 0.20, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (All Time) Calculated using the full available price history since Feb 12, 2026	0.20

Return for Risk

MMK vs. GMMF — Risk / Return Rank

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

MMK

Risk / return metrics aren't available yet — we need at least 12 months of trading data to calculate them.

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

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.

MMK vs. GMMF - Risk-Adjusted Trends Comparison

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

	MMK	GMMF	Difference
Sharpe ratio: Return per unit of total volatility	—	18.81	—
Sortino ratio: Return per unit of downside risk	—	139.19	—
Omega ratio: Gain probability vs. loss probability	—	40.48	—
Calmar ratio: Return relative to maximum drawdown	—	251.34	—
Martin ratio: Return relative to average drawdown	—	2,211.69	—

Drawdowns

MMK vs. GMMF - Drawdown Comparison

The maximum MMK drawdown since its inception was -0.01%, smaller than the maximum GMMF drawdown of -0.03%. Use the drawdown chart below to compare losses from any high point for MMK and GMMF.

Drawdown Indicators

	MMK	GMMF	Difference
Max Drawdown Largest peak-to-trough decline	-0.01%	-0.03%	+0.02%
Max Drawdown (1Y) Largest decline over 1 year	—	-0.01%	—
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%	—

Volatility

Volatility by Period

	MMK	GMMF	Difference
Volatility (1M) Calculated over the trailing 1-month period	—	0.05%	—
Volatility (6M) Calculated over the trailing 6-month period	—	0.13%	—
Volatility (1Y) Calculated over the trailing 1-year period	0.17%	0.20%	-0.03%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	0.17%	0.24%	-0.07%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	0.17%	0.24%	-0.07%

MMK vs. GMMF - Expense Ratio Comparison

MMK has a 0.18% expense ratio, which is lower than GMMF's 0.20% 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

MMK vs. GMMF - Dividend Comparison

MMK's dividend yield for the trailing twelve months is around 1.37%, less than GMMF's 3.79% yield.

Position	TTM	2025
GMMF iShares Government Money Market ETF	3.79%	3.45%
MMK State Street Prime Money Market ETF	1.37%	0.00%

Frequently Asked Questions

Can I hold both MMK and GMMF in my portfolio?

MMK and GMMF have a correlation of 0.20, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which ETF is better, MMK or GMMF?

On fees, MMK is cheaper at 0.18% per year. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF is cheaper, MMK or GMMF?

MMK is cheaper with a 0.18% expense ratio, compared with 0.20% for GMMF.

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

GMMF has the higher dividend yield at 3.79%, compared with 1.37% for MMK.

What is the main difference between MMK and GMMF?

They also come from different issuers: State Street and iShares. Their fees differ too: 0.18% for MMK and 0.20% for GMMF.