IIRMX vs. VEMPX

Last updated Jun 24, 2026

IIRMX (Voya Russell Mid Cap Index Portfolio) and VEMPX (Vanguard Extended Market Index Fund Institutional Plus Shares) are both Mid Cap Blend Equities funds. Over the past 10 years, IIRMX returned 12.05%/yr vs 12.65%/yr for VEMPX. Their correlation of 0.94 suggests significant overlap in exposure. IIRMX charges 0.40%/yr vs 0.04%/yr for VEMPX.

Performance

IIRMX vs. VEMPX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Voya Russell Mid Cap Index Portfolio (IIRMX) and Vanguard Extended Market Index Fund Institutional Plus Shares (VEMPX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, IIRMX achieves a 18.29% return, which is significantly higher than VEMPX's 15.57% return. Both investments have delivered pretty close results over the past 10 years, with IIRMX having a 12.05% annualized return and VEMPX not far ahead at 12.65%.

IIRMX

• 1D: 0.56%
• 1M: 3.31%
• YTD: 18.29%
• 6M: 16.71%
• 1Y: 26.93%
• 3Y*: 18.68%
• 5Y*: 8.95%
• 10Y*: 12.05%

VEMPX

• 1D: -0.12%
• 1M: 4.30%
• YTD: 15.57%
• 6M: 13.22%
• 1Y: 29.41%
• 3Y*: 20.29%
• 5Y*: 6.41%
• 10Y*: 12.65%

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

IIRMX vs. VEMPX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
IIRMX Voya Russell Mid Cap Index Portfolio	18.29%	10.40%	14.78%	16.74%	-17.55%	21.79%	16.04%	29.16%	-9.30%	18.05%
VEMPX Vanguard Extended Market Index Fund Institutional Plus Shares	15.57%	11.43%	15.50%	26.98%	-26.45%	12.48%	32.24%	28.06%	-9.35%	18.13%

Correlation

The correlation between IIRMX and VEMPX is 0.84, 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	0.84
Correlation (3Y) Calculated over the trailing 3-year period	0.85
Correlation (5Y) Calculated over the trailing 5-year period	0.91
Correlation (10Y) Calculated over the trailing 10-year period	0.93
Correlation (All Time) Calculated using the full available price history since Dec 13, 2010	0.94

The correlation between IIRMX and VEMPX shifts across timeframes, from 0.84 (1 year) to 0.94 (all time), reflecting how their relationship changes across market environments.

Return for Risk

IIRMX vs. VEMPX — Risk / Return Rank

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

IIRMX

IIRMX Risk / Return Rank: 53
IIRMX Sharpe Ratio Rank: 28
IIRMX Sortino Ratio Rank: 33
IIRMX Omega Ratio Rank: 48
IIRMX Calmar Ratio Rank: 76
IIRMX Martin Ratio Rank: 80

VEMPX

VEMPX Risk / Return Rank: 47
VEMPX Sharpe Ratio Rank: 41
VEMPX Sortino Ratio Rank: 38
VEMPX Omega Ratio Rank: 36
VEMPX Calmar Ratio Rank: 66
VEMPX Martin Ratio Rank: 55

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.

IIRMX vs. VEMPX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Voya Russell Mid Cap Index Portfolio (IIRMX) and Vanguard Extended Market Index Fund Institutional Plus Shares (VEMPX). 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.

	IIRMX	VEMPX	Difference
Sharpe ratio: Return per unit of total volatility	1.39	1.72	-0.33
Sortino ratio: Return per unit of downside risk	2.20	2.40	-0.20
Omega ratio: Gain probability vs. loss probability	1.35	1.29	+0.05
Calmar ratio: Return relative to maximum drawdown	3.25	2.99	+0.27
Martin ratio: Return relative to average drawdown	13.93	10.49	+3.44

IIRMX vs. VEMPX - Sharpe Ratio Comparison

The current IIRMX Sharpe Ratio is 1.39, which is comparable to the VEMPX Sharpe Ratio of 1.72. The chart below compares the historical Sharpe Ratios of IIRMX and VEMPX, 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

IIRMX vs. VEMPX - Drawdown Comparison

The maximum IIRMX drawdown since its inception was -56.44%, which is greater than VEMPX's maximum drawdown of -41.62%. Use the drawdown chart below to compare losses from any high point for IIRMX and VEMPX.

Drawdown Indicators

	IIRMX	VEMPX	Difference
Max Drawdown Largest peak-to-trough decline	-56.44%	-41.62%	-14.82%
Max Drawdown (1Y) Largest decline over 1 year	-9.61%	-10.25%	+0.64%
Max Drawdown (3Y) Largest decline over 3 years	-21.18%	-26.83%	+5.65%
Max Drawdown (5Y) Largest decline over 5 years	-26.26%	-36.32%	+10.06%
Max Drawdown (10Y) Largest decline over 10 years	-40.41%	-41.62%	+1.21%
Current Drawdown Current decline from peak	-0.22%	-0.24%	+0.02%
Average Drawdown Average peak-to-trough decline	-7.86%	-7.94%	+0.08%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.18%	2.91%	-0.73%

Volatility

IIRMX vs. VEMPX - Volatility Comparison

The current volatility for Voya Russell Mid Cap Index Portfolio (IIRMX) is 4.49%, while Vanguard Extended Market Index Fund Institutional Plus Shares (VEMPX) has a volatility of 6.09%. This indicates that IIRMX experiences smaller price fluctuations and is considered to be less risky than VEMPX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	IIRMX	VEMPX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.49%	6.09%	-1.60%
Volatility (6M) Calculated over the trailing 6-month period	19.50%	13.29%	+6.21%
Volatility (1Y) Calculated over the trailing 1-year period	22.59%	17.84%	+4.75%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	20.39%	22.45%	-2.06%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	20.42%	22.41%	-1.99%

IIRMX vs. VEMPX - Expense Ratio Comparison

IIRMX has a 0.40% expense ratio, which is higher than VEMPX's 0.04% expense ratio.

Dividends

IIRMX vs. VEMPX - Dividend Comparison

IIRMX's dividend yield for the trailing twelve months is around 37.30%, more than VEMPX's 1.01% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
IIRMX Voya Russell Mid Cap Index Portfolio	37.30%	13.19%	10.43%	11.78%	10.34%	10.34%	14.22%	20.78%	15.64%	8.09%	14.11%	10.13%
VEMPX Vanguard Extended Market Index Fund Institutional Plus Shares	1.01%	1.15%	1.11%	1.27%	1.17%	1.15%	1.09%	1.32%	1.68%	1.27%	1.46%	1.39%

Frequently Asked Questions

Can I hold both IIRMX and VEMPX in my portfolio?

IIRMX and VEMPX have a correlation of 0.84, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, IIRMX or VEMPX?

VEMPX has higher volatility (6.09%) compared to IIRMX (4.49%). In terms of maximum drawdown, IIRMX dropped -56.44% vs VEMPX's -41.62%.

Which has better risk-adjusted returns?

VEMPX currently has the higher Sharpe Ratio (1.72 vs 1.39), 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.