MMK vs. PMMF

Last updated Jul 4, 2026

MMK (State Street Prime Money Market ETF) and PMMF (iShares Prime Money Market ETF) are both Money Market funds. Both are actively managed. At a correlation of -0.03, they often move in opposite directions. MMK charges 0.18%/yr vs 0.20%/yr for PMMF.

Performance

MMK vs. PMMF - Performance Comparison

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

Returns By Period

MMK

• 1D: 0.03%
• 1M: 0.31%
• 6M: —
• YTD: —
• 1Y: —
• 3Y*: —
• 5Y*: —
• 10Y*: —

PMMF

• 1D: 0.04%
• 1M: 0.31%
• 6M: 1.81%
• YTD: 1.83%
• 1Y: 3.91%
• 3Y*: —
• 5Y*: —
• 10Y*: —

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

MMK vs. PMMF - Yearly Performance Comparison

	2026 (YTD)
MMK State Street Prime Money Market ETF	1.41%
PMMF iShares Prime Money Market ETF	1.39%

Correlation

The correlation between MMK and PMMF is -0.03, meaning there is essentially no relationship between their price movements. Each responds to its own set of market drivers, making them strong candidates for combining in a diversified portfolio.

	Correlation
Correlation (All Time) Calculated using the full available price history since Feb 12, 2026	-0.03

Return for Risk

MMK vs. PMMF — 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.

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.

MMK vs. PMMF - Risk-Adjusted Trends Comparison

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

	MMK	PMMF	Difference
Sharpe ratio: Return per unit of total volatility	—	20.42	—
Sortino ratio: Return per unit of downside risk	—	98.25	—
Omega ratio: Gain probability vs. loss probability	—	41.70	—
Calmar ratio: Return relative to maximum drawdown	—	158.84	—
Martin ratio: Return relative to average drawdown	—	1,530.18	—

Drawdowns

MMK vs. PMMF - Drawdown Comparison

The maximum MMK drawdown since its inception was -0.01%, smaller than the maximum PMMF drawdown of -0.13%. Use the drawdown chart below to compare losses from any high point for MMK and PMMF.

Drawdown Indicators

	MMK	PMMF	Difference
Max Drawdown Largest peak-to-trough decline	-0.01%	-0.13%	+0.12%
Max Drawdown (1Y) Largest decline over 1 year	—	-0.02%	—
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	PMMF	Difference
Volatility (1M) Calculated over the trailing 1-month period	—	0.06%	—
Volatility (6M) Calculated over the trailing 6-month period	—	0.13%	—
Volatility (1Y) Calculated over the trailing 1-year period	0.18%	0.19%	-0.01%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	0.18%	0.35%	-0.17%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	0.18%	0.35%	-0.17%

MMK vs. PMMF - Expense Ratio Comparison

MMK has a 0.18% expense ratio, which is lower than PMMF'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. PMMF - Dividend Comparison

MMK's dividend yield for the trailing twelve months is around 1.38%, less than PMMF's 3.78% yield.

Position	TTM	2025
MMK State Street Prime Money Market ETF	1.38%	0.00%
PMMF iShares Prime Money Market ETF	3.78%	3.59%

Frequently Asked Questions

Can I hold both MMK and PMMF in my portfolio?

MMK and PMMF have a correlation of -0.03, 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 PMMF?

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 PMMF?

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

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

PMMF has the higher dividend yield at 3.78%, compared with 1.38% for MMK.

What is the main difference between MMK and PMMF?

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