SPIAX vs. MIEYX

Last updated Jun 24, 2026

SPIAX (Invesco S&P 500 Index A) and MIEYX (MM S&P 500 Index Fund) are both S&P 500 funds - SPIAX tracks the S&P 500 while MIEYX tracks the S&P 500 Index. Both are passively managed. Over the past 10 years, SPIAX returned 15.18%/yr vs 14.74%/yr for MIEYX. With a 0.99 correlation, they move nearly in lockstep. SPIAX charges 0.54%/yr vs 0.46%/yr for MIEYX.

Performance

SPIAX vs. MIEYX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Invesco S&P 500 Index A (SPIAX) and MM S&P 500 Index Fund (MIEYX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both stocks are quite close, with SPIAX having a 9.53% return and MIEYX slightly lower at 9.52%. Both investments have delivered pretty close results over the past 10 years, with SPIAX having a 15.18% annualized return and MIEYX not far behind at 14.74%.

SPIAX

• 1D: -0.37%
• 1M: 0.05%
• YTD: 9.53%
• 6M: 8.51%
• 1Y: 24.91%
• 3Y*: 20.75%
• 5Y*: 13.01%
• 10Y*: 15.18%

MIEYX

• 1D: -0.39%
• 1M: 0.07%
• YTD: 9.52%
• 6M: 8.51%
• 1Y: 24.87%
• 3Y*: 20.83%
• 5Y*: 13.01%
• 10Y*: 14.74%

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

SPIAX vs. MIEYX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
SPIAX Invesco S&P 500 Index A	9.53%	17.23%	24.34%	25.63%	-18.56%	27.99%	17.84%	30.78%	-4.97%	21.13%
MIEYX MM S&P 500 Index Fund	9.52%	17.27%	24.36%	25.76%	-18.63%	28.02%	17.87%	30.98%	-5.26%	18.90%

Correlation

The correlation between SPIAX and MIEYX 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	0.98
Correlation (5Y) Calculated over the trailing 5-year period	0.99
Correlation (10Y) Calculated over the trailing 10-year period	0.99
Correlation (All Time) Calculated using the full available price history since Feb 27, 1998	0.99

The correlation between SPIAX and MIEYX has been stable across timeframes, ranging from 0.98 to 1.00 - a consistent structural relationship.

Return for Risk

SPIAX vs. MIEYX — Risk / Return Rank

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

SPIAX

SPIAX Risk / Return Rank: 62
SPIAX Sharpe Ratio Rank: 61
SPIAX Sortino Ratio Rank: 54
SPIAX Omega Ratio Rank: 57
SPIAX Calmar Ratio Rank: 64
SPIAX Martin Ratio Rank: 74

MIEYX

MIEYX Risk / Return Rank: 62
MIEYX Sharpe Ratio Rank: 60
MIEYX Sortino Ratio Rank: 54
MIEYX Omega Ratio Rank: 56
MIEYX Calmar Ratio Rank: 64
MIEYX Martin Ratio Rank: 75

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.

SPIAX vs. MIEYX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Invesco S&P 500 Index A (SPIAX) and MM S&P 500 Index Fund (MIEYX). 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.

	SPIAX	MIEYX	Difference
Sharpe ratio: Return per unit of total volatility	2.11	2.10	+0.01
Sortino ratio: Return per unit of downside risk	2.85	2.84	+0.01
Omega ratio: Gain probability vs. loss probability	1.38	1.38	0.00
Calmar ratio: Return relative to maximum drawdown	2.94	2.94	0.00
Martin ratio: Return relative to average drawdown	13.19	13.21	-0.02

SPIAX vs. MIEYX - Sharpe Ratio Comparison

The current SPIAX Sharpe Ratio is 2.11, which is comparable to the MIEYX Sharpe Ratio of 2.10. The chart below compares the historical Sharpe Ratios of SPIAX and MIEYX, 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

SPIAX vs. MIEYX - Drawdown Comparison

The maximum SPIAX drawdown since its inception was -55.47%, roughly equal to the maximum MIEYX drawdown of -55.63%. Use the drawdown chart below to compare losses from any high point for SPIAX and MIEYX.

Drawdown Indicators

	SPIAX	MIEYX	Difference
Max Drawdown Largest peak-to-trough decline	-55.47%	-55.63%	+0.16%
Max Drawdown (1Y) Largest decline over 1 year	-8.97%	-8.92%	-0.05%
Max Drawdown (3Y) Largest decline over 3 years	-18.84%	-36.63%	+17.79%
Max Drawdown (5Y) Largest decline over 5 years	-24.81%	-36.63%	+11.82%
Max Drawdown (10Y) Largest decline over 10 years	-33.84%	-36.63%	+2.79%
Current Drawdown Current decline from peak	-1.75%	-4.12%	+2.37%
Average Drawdown Average peak-to-trough decline	-10.76%	-12.55%	+1.79%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.99%	1.98%	+0.01%

Volatility

SPIAX vs. MIEYX - Volatility Comparison

Invesco S&P 500 Index A (SPIAX) and MM S&P 500 Index Fund (MIEYX) have volatilities of 4.67% and 4.69%, 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

	SPIAX	MIEYX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.67%	4.69%	-0.02%
Volatility (6M) Calculated over the trailing 6-month period	9.92%	9.84%	+0.08%
Volatility (1Y) Calculated over the trailing 1-year period	12.54%	12.52%	+0.02%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.00%	25.57%	-8.57%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.13%	22.61%	-4.48%

SPIAX vs. MIEYX - Expense Ratio Comparison

SPIAX has a 0.54% expense ratio, which is higher than MIEYX's 0.46% expense ratio.

Dividends

SPIAX vs. MIEYX - Dividend Comparison

SPIAX's dividend yield for the trailing twelve months is around 0.93%, less than MIEYX's 16.10% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MIEYX MM S&P 500 Index Fund	16.10%	17.63%	32.89%	7.13%	33.24%	13.29%	16.29%	6.38%	19.14%	21.81%	4.19%	2.29%
SPIAX Invesco S&P 500 Index A	0.93%	1.01%	1.08%	1.04%	1.07%	1.90%	1.26%	1.93%	2.59%	1.28%	1.28%	1.53%

Frequently Asked Questions

Can I hold both SPIAX and MIEYX in my portfolio?

With a correlation of 1.00, SPIAX and MIEYX 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, SPIAX or MIEYX?

MIEYX has higher volatility (4.69%) compared to SPIAX (4.67%). In terms of maximum drawdown, SPIAX dropped -55.47% vs MIEYX's -55.63%.

Which has better risk-adjusted returns?

SPIAX currently has the higher Sharpe Ratio (2.11 vs 2.10), 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.