PEXMX vs. PREIX

Last updated Jun 23, 2026

PEXMX (T. Rowe Price Extended Equity Market Index Fund) and PREIX (T. Rowe Price Equity Index 500 Fund) are both mutual funds - PEXMX is a Mid Cap Growth Equities fund managed by T. Rowe Price, while PREIX is a Large Cap Blend Equities fund tracking the S&P 500 Index. Over the past 10 years, PEXMX returned 12.36%/yr vs 15.34%/yr for PREIX. Their correlation of 0.88 suggests significant overlap in exposure. PEXMX charges 0.23%/yr vs 0.15%/yr for PREIX.

Performance

PEXMX vs. PREIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in T. Rowe Price Extended Equity Market Index Fund (PEXMX) and T. Rowe Price Equity Index 500 Fund (PREIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, PEXMX achieves a 15.35% return, which is significantly higher than PREIX's 10.08% return. Over the past 10 years, PEXMX has underperformed PREIX with an annualized return of 12.36%, while PREIX has yielded a comparatively higher 15.34% annualized return.

PEXMX

• 1D: 1.66%
• 1M: 4.39%
• YTD: 15.35%
• 6M: 12.36%
• 1Y: 30.22%
• 3Y*: 18.90%
• 5Y*: 6.86%
• 10Y*: 12.36%

PREIX

• 1D: 1.08%
• 1M: 0.45%
• YTD: 10.08%
• 6M: 9.58%
• 1Y: 26.95%
• 3Y*: 20.76%
• 5Y*: 13.90%
• 10Y*: 15.34%

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

PEXMX vs. PREIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PEXMX T. Rowe Price Extended Equity Market Index Fund	15.35%	11.17%	16.72%	25.32%	-26.15%	12.09%	30.80%	32.57%	-9.61%	16.63%
PREIX T. Rowe Price Equity Index 500 Fund	10.08%	17.66%	24.78%	26.07%	-18.27%	28.48%	18.17%	31.47%	-4.59%	21.01%

Correlation

The correlation between PEXMX and PREIX is 0.81, 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	0.81
Correlation (3Y) Calculated over the trailing 3-year period	0.81
Correlation (5Y) Calculated over the trailing 5-year period	0.85
Correlation (10Y) Calculated over the trailing 10-year period	0.85
Correlation (All Time) Calculated using the full available price history since Jan 30, 1998	0.88

The correlation between PEXMX and PREIX has been stable across timeframes, ranging from 0.81 to 0.88 - a consistent structural relationship.

Return for Risk

PEXMX vs. PREIX — Risk / Return Rank

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

PEXMX

PEXMX Risk / Return Rank: 47
PEXMX Sharpe Ratio Rank: 40
PEXMX Sortino Ratio Rank: 39
PEXMX Omega Ratio Rank: 35
PEXMX Calmar Ratio Rank: 67
PEXMX Martin Ratio Rank: 55

PREIX

PREIX Risk / Return Rank: 65
PREIX Sharpe Ratio Rank: 63
PREIX Sortino Ratio Rank: 57
PREIX Omega Ratio Rank: 60
PREIX Calmar Ratio Rank: 67
PREIX Martin Ratio Rank: 78

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.

PEXMX vs. PREIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for T. Rowe Price Extended Equity Market Index Fund (PEXMX) and T. Rowe Price Equity Index 500 Fund (PREIX). 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.

	PEXMX	PREIX	Difference
Sharpe ratio: Return per unit of total volatility	1.71	2.15	-0.44
Sortino ratio: Return per unit of downside risk	2.42	2.90	-0.48
Omega ratio: Gain probability vs. loss probability	1.29	1.39	-0.10
Calmar ratio: Return relative to maximum drawdown	3.00	3.00	0.00
Martin ratio: Return relative to average drawdown	10.54	13.55	-3.01

PEXMX vs. PREIX - Sharpe Ratio Comparison

The current PEXMX Sharpe Ratio is 1.71, which is comparable to the PREIX Sharpe Ratio of 2.15. The chart below compares the historical Sharpe Ratios of PEXMX and PREIX, 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

PEXMX vs. PREIX - Drawdown Comparison

The maximum PEXMX drawdown since its inception was -57.82%, roughly equal to the maximum PREIX drawdown of -55.32%. Use the drawdown chart below to compare losses from any high point for PEXMX and PREIX.

Drawdown Indicators

	PEXMX	PREIX	Difference
Max Drawdown Largest peak-to-trough decline	-57.82%	-55.32%	-2.50%
Max Drawdown (1Y) Largest decline over 1 year	-10.30%	-8.93%	-1.37%
Max Drawdown (3Y) Largest decline over 3 years	-27.01%	-18.78%	-8.23%
Max Drawdown (5Y) Largest decline over 5 years	-36.27%	-24.60%	-11.67%
Max Drawdown (10Y) Largest decline over 10 years	-41.27%	-33.81%	-7.46%
Current Drawdown Current decline from peak	-0.12%	-1.37%	+1.25%
Average Drawdown Average peak-to-trough decline	-13.60%	-8.72%	-4.88%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.91%	1.97%	+0.94%

Volatility

PEXMX vs. PREIX - Volatility Comparison

T. Rowe Price Extended Equity Market Index Fund (PEXMX) has a higher volatility of 6.35% compared to T. Rowe Price Equity Index 500 Fund (PREIX) at 4.77%. This indicates that PEXMX's price experiences larger fluctuations and is considered to be riskier than PREIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	PEXMX	PREIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.35%	4.77%	+1.58%
Volatility (6M) Calculated over the trailing 6-month period	13.74%	9.91%	+3.83%
Volatility (1Y) Calculated over the trailing 1-year period	18.12%	12.48%	+5.64%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.57%	17.09%	+5.48%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.30%	18.15%	+4.15%

PEXMX vs. PREIX - Expense Ratio Comparison

PEXMX has a 0.23% expense ratio, which is higher than PREIX's 0.15% expense ratio. However, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

PEXMX vs. PREIX - Dividend Comparison

PEXMX's dividend yield for the trailing twelve months is around 3.49%, more than PREIX's 2.13% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PEXMX T. Rowe Price Extended Equity Market Index Fund	3.49%	4.02%	7.64%	3.64%	7.53%	14.87%	2.99%	8.17%	6.67%	4.50%	5.90%	4.81%
PREIX T. Rowe Price Equity Index 500 Fund	2.13%	2.32%	1.17%	1.32%	1.50%	1.56%	1.97%	2.13%	2.60%	1.30%	2.03%	2.02%

Frequently Asked Questions

Can I hold both PEXMX and PREIX in my portfolio?

PEXMX and PREIX have a correlation of 0.81, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, PEXMX or PREIX?

PEXMX has higher volatility (6.35%) compared to PREIX (4.77%). In terms of maximum drawdown, PEXMX dropped -57.82% vs PREIX's -55.32%.

Which has better risk-adjusted returns?

PREIX currently has the higher Sharpe Ratio (2.15 vs 1.71), 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.