PEXMX vs. PRDSX

Last updated Jun 3, 2026

PEXMX (T. Rowe Price Extended Equity Market Index Fund) and PRDSX (T. Rowe Price QM U.S. Small-Cap Growth Equity Fund) are both mutual funds - PEXMX is a Mid Cap Growth Equities fund managed by T. Rowe Price, while PRDSX is a Small Cap Growth Equities fund managed by T. Rowe Price. Over the past 10 years, PEXMX returned 12.10%/yr vs 11.61%/yr for PRDSX. With a 0.97 correlation, they move nearly in lockstep. PEXMX charges 0.23%/yr vs 0.78%/yr for PRDSX.

Performance

PEXMX vs. PRDSX - 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 QM U.S. Small-Cap Growth Equity Fund (PRDSX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both investments are quite close, with PEXMX having a 13.41% return and PRDSX slightly higher at 13.71%. Both investments have delivered pretty close results over the past 10 years, with PEXMX having a 12.10% annualized return and PRDSX not far behind at 11.61%.

PEXMX

• 1D: 0.28%
• 1M: 4.27%
• YTD: 13.41%
• 6M: 13.60%
• 1Y: 30.17%
• 3Y*: 19.44%
• 5Y*: 6.40%
• 10Y*: 12.10%

PRDSX

• 1D: -0.70%
• 1M: 2.59%
• YTD: 13.71%
• 6M: 14.11%
• 1Y: 29.46%
• 3Y*: 16.13%
• 5Y*: 7.22%
• 10Y*: 11.61%

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

PEXMX vs. PRDSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PEXMX T. Rowe Price Extended Equity Market Index Fund	13.41%	11.17%	16.72%	25.32%	-26.15%	12.09%	30.80%	32.57%	-9.61%	16.63%
PRDSX T. Rowe Price QM U.S. Small-Cap Growth Equity Fund	13.71%	10.10%	12.97%	21.15%	-22.49%	11.15%	23.85%	32.75%	-6.91%	22.12%

Correlation

The correlation between PEXMX and PRDSX is 0.92, 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	0.92
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 Feb 2, 1998	0.97

The correlation between PEXMX and PRDSX has been stable across timeframes, ranging from 0.92 to 0.97 - a consistent structural relationship.

Return for Risk

PEXMX vs. PRDSX — Risk / Return Rank

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

PEXMX

PEXMX Risk / Return Rank: 41
PEXMX Sharpe Ratio Rank: 38
PEXMX Sortino Ratio Rank: 37
PEXMX Omega Ratio Rank: 34
PEXMX Calmar Ratio Rank: 51
PEXMX Martin Ratio Rank: 47

PRDSX

PRDSX Risk / Return Rank: 35
PRDSX Sharpe Ratio Rank: 31
PRDSX Sortino Ratio Rank: 30
PRDSX Omega Ratio Rank: 28
PRDSX Calmar Ratio Rank: 41
PRDSX Martin Ratio Rank: 45

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. PRDSX - 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 QM U.S. Small-Cap Growth Equity Fund (PRDSX). 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.

	PEXMX	PRDSX	Difference
Sharpe ratio Return per unit of total volatility	1.80	1.61	+0.19
Sortino ratio Return per unit of downside risk	2.55	2.32	+0.23
Omega ratio Gain probability vs. loss probability	1.31	1.28	+0.03
Calmar ratio Return relative to maximum drawdown	2.77	2.49	+0.28
Martin ratio Return relative to average drawdown	9.90	9.66	+0.25
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

PEXMX vs. PRDSX - Sharpe Ratio Comparison

The current PEXMX Sharpe Ratio is 1.80, which is comparable to the PRDSX Sharpe Ratio of 1.61. The chart below compares the historical Sharpe Ratios of PEXMX and PRDSX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Sharpe Ratios by Period

	PEXMX	PRDSX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.80	1.61	+0.19
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.29	0.34	-0.05
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.55	0.54	+0.01
Sharpe Ratio (All Time) Calculated using the full available price history	0.40	0.37	+0.03

Drawdowns

PEXMX vs. PRDSX - Drawdown Comparison

The maximum PEXMX drawdown since its inception was -57.82%, roughly equal to the maximum PRDSX drawdown of -58.95%. Use the drawdown chart below to compare losses from any high point for PEXMX and PRDSX.

Drawdown Indicators

	PEXMX	PRDSX	Difference
Max Drawdown Largest peak-to-trough decline	-57.82%	-58.95%	+1.13%
Max Drawdown (1Y) Largest decline over 1 year	-10.30%	-12.08%	+1.78%
Max Drawdown (3Y) Largest decline over 3 years	-27.01%	-25.84%	-1.17%
Max Drawdown (5Y) Largest decline over 5 years	-36.27%	-33.17%	-3.10%
Max Drawdown (10Y) Largest decline over 10 years	-41.27%	-37.61%	-3.66%
Current Drawdown Current decline from peak	0.00%	-1.24%	+1.24%
Average Drawdown Average peak-to-trough decline	-13.62%	-14.16%	+0.54%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.88%	3.11%	-0.23%

Volatility

PEXMX vs. PRDSX - Volatility Comparison

The current volatility for T. Rowe Price Extended Equity Market Index Fund (PEXMX) is 4.61%, while T. Rowe Price QM U.S. Small-Cap Growth Equity Fund (PRDSX) has a volatility of 5.98%. This indicates that PEXMX experiences smaller price fluctuations and is considered to be less risky than PRDSX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	PEXMX	PRDSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.61%	5.98%	-1.37%
Volatility (6M) Calculated over the trailing 6-month period	13.21%	14.74%	-1.53%
Volatility (1Y) Calculated over the trailing 1-year period	17.50%	18.84%	-1.34%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.45%	21.37%	+1.08%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.25%	21.51%	+0.74%

PEXMX vs. PRDSX - Expense Ratio Comparison

PEXMX has a 0.23% expense ratio, which is lower than PRDSX's 0.78% expense ratio.

Dividends

PEXMX vs. PRDSX - Dividend Comparison

PEXMX's dividend yield for the trailing twelve months is around 3.55%, less than PRDSX's 5.58% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PEXMX T. Rowe Price Extended Equity Market Index Fund	3.55%	4.02%	7.64%	3.64%	7.53%	14.87%	2.99%	8.17%	6.67%	4.50%	5.90%	4.81%
PRDSX T. Rowe Price QM U.S. Small-Cap Growth Equity Fund	5.58%	6.35%	7.96%	2.43%	3.72%	13.97%	2.91%	4.12%	4.53%	0.10%	0.02%	1.83%

Frequently Asked Questions

Can I hold both PEXMX and PRDSX in my portfolio?

With a correlation of 0.92, PEXMX and PRDSX 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 PRDSX?

PRDSX has higher volatility (5.98%) compared to PEXMX (4.61%). In terms of maximum drawdown, PEXMX dropped -57.82% vs PRDSX's -58.95%.

Which has better risk-adjusted returns?

PEXMX currently has the higher Sharpe Ratio (1.80 vs 1.61), 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.