MIGYX vs. VIIIX

Last updated Jul 17, 2026

MIGYX (Invesco Main Street Fund Class Y) and VIIIX (Vanguard Institutional Index Fund Institutional Plus Shares) are both mutual funds - MIGYX is a Large Cap Blend Equities fund actively managed by Invesco, while VIIIX is a S&P 500 fund tracking the S&P 500 Index. MIGYX is actively managed, while VIIIX is passively managed. Over the past 10 years, MIGYX returned 11.93%/yr vs 15.33%/yr for VIIIX. With a 0.97 correlation, they move nearly in lockstep. MIGYX charges 0.56%/yr vs 0.02%/yr for VIIIX.

Performance

MIGYX vs. VIIIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Invesco Main Street Fund Class Y (MIGYX) and Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MIGYX achieves a 8.23% return, which is significantly lower than VIIIX's 11.31% return. Over the past 10 years, MIGYX has underperformed VIIIX with an annualized return of 11.93%, while VIIIX has yielded a comparatively higher 15.33% annualized return.

MIGYX

• 1D: 0.69%
• 1M: 1.86%
• 6M: 7.69%
• YTD: 8.23%
• 1Y: 16.12%
• 3Y*: 17.40%
• 5Y*: 11.00%
• 10Y*: 11.93%

VIIIX

• 1D: 0.39%
• 1M: 0.88%
• 6M: 9.67%
• YTD: 11.31%
• 1Y: 22.32%
• 3Y*: 20.90%
• 5Y*: 13.59%
• 10Y*: 15.33%

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

MIGYX vs. VIIIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MIGYX Invesco Main Street Fund Class Y	8.23%	16.31%	23.93%	23.33%	-20.02%	27.65%	14.68%	22.67%	-8.04%	17.04%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	11.31%	17.87%	26.29%	25.79%	-18.14%	28.69%	18.41%	31.48%	-4.41%	21.82%

Correlation

The correlation between MIGYX and VIIIX is 0.88, indicating a strong positive relationship between their price movements. Combining them offers limited diversification - they tend to fall together during downturns.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.88
Correlation (3Y) Calculated over the trailing 3-year period	0.94
Correlation (5Y) Calculated over the trailing 5-year period	0.96
Correlation (10Y) Calculated over the trailing 10-year period	0.96
Correlation (All Time) Calculated using the full available price history since Jul 7, 1997	0.97

The correlation between MIGYX and VIIIX has been stable across timeframes, ranging from 0.88 to 0.97 - a consistent structural relationship.

Return for Risk

MIGYX vs. VIIIX — Risk / Return Rank

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

MIGYX

MIGYX Risk / Return Rank: 35
MIGYX Sharpe Ratio Rank: 36
MIGYX Sortino Ratio Rank: 37
MIGYX Omega Ratio Rank: 35
MIGYX Calmar Ratio Rank: 29
MIGYX Martin Ratio Rank: 36

VIIIX

VIIIX Risk / Return Rank: 69
VIIIX Sharpe Ratio Rank: 68
VIIIX Sortino Ratio Rank: 63
VIIIX Omega Ratio Rank: 65
VIIIX Calmar Ratio Rank: 69
VIIIX Martin Ratio Rank: 80

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.

MIGYX vs. VIIIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Invesco Main Street Fund Class Y (MIGYX) and Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX). 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.

	MIGYX	VIIIX	Difference
Sharpe ratio: Return per unit of total volatility	1.41	1.82	-0.41
Sortino ratio: Return per unit of downside risk	2.05	2.49	-0.44
Omega ratio: Gain probability vs. loss probability	1.26	1.33	-0.07
Calmar ratio: Return relative to maximum drawdown	1.68	2.56	-0.89
Martin ratio: Return relative to average drawdown	6.74	11.25	-4.51

MIGYX vs. VIIIX - Sharpe Ratio Comparison

The current MIGYX Sharpe Ratio is 1.41, which is comparable to the VIIIX Sharpe Ratio of 1.82. The chart below compares the historical Sharpe Ratios of MIGYX and VIIIX, 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

MIGYX vs. VIIIX - Drawdown Comparison

The maximum MIGYX drawdown since its inception was -56.98%, roughly equal to the maximum VIIIX drawdown of -55.18%. Use the drawdown chart below to compare losses from any high point for MIGYX and VIIIX.

Drawdown Indicators

	MIGYX	VIIIX	Difference
Max Drawdown Largest peak-to-trough decline	-56.98%	-55.18%	-1.80%
Max Drawdown (1Y) Largest decline over 1 year	-10.87%	-8.90%	-1.97%
Max Drawdown (3Y) Largest decline over 3 years	-19.88%	-18.75%	-1.13%
Max Drawdown (5Y) Largest decline over 5 years	-26.59%	-24.50%	-2.09%
Max Drawdown (10Y) Largest decline over 10 years	-35.48%	-33.79%	-1.69%
Current Drawdown Current decline from peak	0.00%	-0.35%	+0.35%
Average Drawdown Average peak-to-trough decline	-10.57%	-9.98%	-0.59%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.57%	2.02%	+0.55%

Volatility

MIGYX vs. VIIIX - Volatility Comparison

Invesco Main Street Fund Class Y (MIGYX) has a higher volatility of 3.85% compared to Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) at 3.61%. This indicates that MIGYX's price experiences larger fluctuations and is considered to be riskier than VIIIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MIGYX	VIIIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.85%	3.61%	+0.24%
Volatility (6M) Calculated over the trailing 6-month period	10.06%	9.99%	+0.07%
Volatility (1Y) Calculated over the trailing 1-year period	12.96%	12.55%	+0.41%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.03%	17.00%	+0.03%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	17.90%	18.05%	-0.15%

MIGYX vs. VIIIX - Expense Ratio Comparison

MIGYX has a 0.56% expense ratio, which is higher than VIIIX's 0.02% expense ratio.

Dividends

MIGYX vs. VIIIX - Dividend Comparison

MIGYX's dividend yield for the trailing twelve months is around 7.22%, more than VIIIX's 2.47% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MIGYX Invesco Main Street Fund Class Y	7.22%	7.82%	6.36%	7.51%	5.01%	19.63%	3.23%	0.98%	20.13%	7.80%	3.22%	14.18%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	2.47%	2.11%	3.66%	2.66%	3.39%	4.79%	3.07%	2.86%	2.45%	1.84%	2.38%	2.47%

Frequently Asked Questions

Can I hold both MIGYX and VIIIX in my portfolio?

MIGYX and VIIIX have a correlation of 0.88, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, MIGYX or VIIIX?

MIGYX has higher volatility (3.85%) compared to VIIIX (3.61%). In terms of maximum drawdown, MIGYX dropped -56.98% vs VIIIX's -55.18%.

Which has better risk-adjusted returns?

VIIIX currently has the higher Sharpe Ratio (1.82 vs 1.41), 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.