PEXMX vs. PRDMX

Last updated Jun 24, 2026

PEXMX (T. Rowe Price Extended Equity Market Index Fund) and PRDMX (T. Rowe Price Diversified Mid Cap Growth Fund) are both Mid Cap Growth Equities funds from T. Rowe Price. Over the past 10 years, PEXMX returned 12.66%/yr vs 13.49%/yr for PRDMX. Their correlation of 0.94 suggests significant overlap in exposure. PEXMX charges 0.23%/yr vs 0.79%/yr for PRDMX.

Performance

PEXMX vs. PRDMX - 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 Diversified Mid Cap Growth Fund (PRDMX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, PEXMX achieves a 15.23% return, which is significantly higher than PRDMX's 5.52% return. Over the past 10 years, PEXMX has underperformed PRDMX with an annualized return of 12.66%, while PRDMX has yielded a comparatively higher 13.49% annualized return.

PEXMX

• 1D: -0.10%
• 1M: 4.28%
• YTD: 15.23%
• 6M: 12.88%
• 1Y: 28.97%
• 3Y*: 20.05%
• 5Y*: 6.31%
• 10Y*: 12.66%

PRDMX

• 1D: 0.43%
• 1M: 3.24%
• YTD: 5.52%
• 6M: 3.40%
• 1Y: 7.90%
• 3Y*: 16.26%
• 5Y*: 6.67%
• 10Y*: 13.49%

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

PEXMX vs. PRDMX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PEXMX T. Rowe Price Extended Equity Market Index Fund	15.23%	11.17%	16.72%	25.32%	-26.15%	12.09%	30.80%	32.57%	-9.61%	16.63%
PRDMX T. Rowe Price Diversified Mid Cap Growth Fund	5.52%	10.30%	23.77%	20.75%	-24.65%	13.56%	31.82%	37.91%	-3.15%	24.66%

Correlation

The correlation between PEXMX and PRDMX is 0.90, 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	0.90
Correlation (3Y) Calculated over the trailing 3-year period	0.90
Correlation (5Y) Calculated over the trailing 5-year period	0.93
Correlation (10Y) Calculated over the trailing 10-year period	0.91
Correlation (All Time) Calculated using the full available price history since Jan 2, 2004	0.94

The correlation between PEXMX and PRDMX has been stable across timeframes, ranging from 0.90 to 0.94 - a consistent structural relationship.

Return for Risk

PEXMX vs. PRDMX — Risk / Return Rank

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

PEXMX

PEXMX Risk / Return Rank: 48
PEXMX Sharpe Ratio Rank: 40
PEXMX Sortino Ratio Rank: 39
PEXMX Omega Ratio Rank: 36
PEXMX Calmar Ratio Rank: 67
PEXMX Martin Ratio Rank: 56

PRDMX

PRDMX Risk / Return Rank: 7
PRDMX Sharpe Ratio Rank: 7
PRDMX Sortino Ratio Rank: 7
PRDMX Omega Ratio Rank: 7
PRDMX Calmar Ratio Rank: 7
PRDMX Martin Ratio Rank: 8

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. PRDMX - 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 Diversified Mid Cap Growth Fund (PRDMX). 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	PRDMX	Difference
Sharpe ratio: Return per unit of total volatility	1.72	0.51	+1.21
Sortino ratio: Return per unit of downside risk	2.43	0.84	+1.59
Omega ratio: Gain probability vs. loss probability	1.29	1.10	+0.20
Calmar ratio: Return relative to maximum drawdown	3.02	0.63	+2.39
Martin ratio: Return relative to average drawdown	10.58	1.96	+8.61

PEXMX vs. PRDMX - Sharpe Ratio Comparison

The current PEXMX Sharpe Ratio is 1.72, which is higher than the PRDMX Sharpe Ratio of 0.51. The chart below compares the historical Sharpe Ratios of PEXMX and PRDMX, 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. PRDMX - Drawdown Comparison

The maximum PEXMX drawdown since its inception was -57.82%, roughly equal to the maximum PRDMX drawdown of -57.57%. Use the drawdown chart below to compare losses from any high point for PEXMX and PRDMX.

Drawdown Indicators

	PEXMX	PRDMX	Difference
Max Drawdown Largest peak-to-trough decline	-57.82%	-57.57%	-0.25%
Max Drawdown (1Y) Largest decline over 1 year	-10.30%	-14.15%	+3.85%
Max Drawdown (3Y) Largest decline over 3 years	-27.01%	-25.06%	-1.95%
Max Drawdown (5Y) Largest decline over 5 years	-36.27%	-35.69%	-0.58%
Max Drawdown (10Y) Largest decline over 10 years	-41.27%	-35.91%	-5.36%
Current Drawdown Current decline from peak	-0.22%	-0.05%	-0.17%
Average Drawdown Average peak-to-trough decline	-13.60%	-8.42%	-5.18%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.90%	4.52%	-1.62%

Volatility

PEXMX vs. PRDMX - Volatility Comparison

T. Rowe Price Extended Equity Market Index Fund (PEXMX) and T. Rowe Price Diversified Mid Cap Growth Fund (PRDMX) have volatilities of 6.05% and 5.89%, 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

	PEXMX	PRDMX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.05%	5.89%	+0.16%
Volatility (6M) Calculated over the trailing 6-month period	13.74%	13.74%	0.00%
Volatility (1Y) Calculated over the trailing 1-year period	18.15%	17.44%	+0.71%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.56%	21.90%	+0.66%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.30%	21.43%	+0.87%

PEXMX vs. PRDMX - Expense Ratio Comparison

PEXMX has a 0.23% expense ratio, which is lower than PRDMX's 0.79% expense ratio.

Dividends

PEXMX vs. PRDMX - Dividend Comparison

PEXMX's dividend yield for the trailing twelve months is around 3.49%, less than PRDMX's 7.34% 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%
PRDMX T. Rowe Price Diversified Mid Cap Growth Fund	7.34%	7.75%	8.59%	6.83%	1.22%	10.13%	4.80%	2.02%	5.23%	3.71%	1.23%	3.78%

Frequently Asked Questions

Can I hold both PEXMX and PRDMX in my portfolio?

With a correlation of 0.90, PEXMX and PRDMX 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, PEXMX or PRDMX?

PEXMX has higher volatility (6.05%) compared to PRDMX (5.89%). In terms of maximum drawdown, PEXMX dropped -57.82% vs PRDMX's -57.57%.

Which has better risk-adjusted returns?

PEXMX currently has the higher Sharpe Ratio (1.72 vs 0.51), 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.