PEXMX vs. MMGPX

Last updated Jul 15, 2026

PEXMX (T. Rowe Price Extended Equity Market Index Fund) and MMGPX (Morgan Stanley Discovery Portfolio) are both Mid Cap Growth Equities funds. Over the past 5 years, PEXMX returned 6.75%/yr vs -5.76%/yr for MMGPX. A 0.76 correlation means they provide meaningful diversification when combined. PEXMX charges 0.23%/yr vs 0.04%/yr for MMGPX.

Performance

PEXMX vs. MMGPX - 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 Morgan Stanley Discovery Portfolio (MMGPX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, PEXMX achieves a 14.75% return, which is significantly higher than MMGPX's 0.41% return.

PEXMX

• 1D: -0.89%
• 1M: 0.47%
• 6M: 9.44%
• YTD: 14.75%
• 1Y: 22.16%
• 3Y*: 17.23%
• 5Y*: 6.75%
• 10Y*: 11.93%

MMGPX

• 1D: -2.14%
• 1M: 2.81%
• 6M: -5.17%
• YTD: 0.41%
• 1Y: -7.10%
• 3Y*: 19.43%
• 5Y*: -5.76%
• 10Y*: —

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

PEXMX vs. MMGPX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PEXMX T. Rowe Price Extended Equity Market Index Fund	14.75%	11.17%	16.72%	25.32%	-26.15%	12.09%	30.80%	32.57%	-9.61%	14.28%
MMGPX Morgan Stanley Discovery Portfolio	0.41%	12.58%	41.83%	44.34%	-63.37%	-11.55%	152.67%	40.20%	10.89%	28.18%

Correlation

The correlation between PEXMX and MMGPX is 0.74, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.74
Correlation (3Y) Calculated over the trailing 3-year period	0.80
Correlation (5Y) Calculated over the trailing 5-year period	0.83
Correlation (All Time) Calculated using the full available price history since Feb 1, 2017	0.76

The correlation between PEXMX and MMGPX has been stable across timeframes, ranging from 0.74 to 0.83 - a consistent structural relationship.

Return for Risk

PEXMX vs. MMGPX — Risk / Return Rank

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

PEXMX

PEXMX Risk / Return Rank: 42
PEXMX Sharpe Ratio Rank: 36
PEXMX Sortino Ratio Rank: 37
PEXMX Omega Ratio Rank: 33
PEXMX Calmar Ratio Rank: 57
PEXMX Martin Ratio Rank: 49

MMGPX

MMGPX Risk / Return Rank: 2
MMGPX Sharpe Ratio Rank: 2
MMGPX Sortino Ratio Rank: 2
MMGPX Omega Ratio Rank: 2
MMGPX Calmar Ratio Rank: 2
MMGPX Martin Ratio Rank: 2

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. MMGPX - 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 Morgan Stanley Discovery Portfolio (MMGPX). 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	MMGPX	Difference
Sharpe ratio: Return per unit of total volatility	1.32	-0.20	+1.52
Sortino ratio: Return per unit of downside risk	1.93	-0.09	+2.03
Omega ratio: Gain probability vs. loss probability	1.23	0.99	+0.24
Calmar ratio: Return relative to maximum drawdown	2.31	-0.21	+2.52
Martin ratio: Return relative to average drawdown	8.07	-0.41	+8.48

PEXMX vs. MMGPX - Sharpe Ratio Comparison

The current PEXMX Sharpe Ratio is 1.32, which is higher than the MMGPX Sharpe Ratio of -0.20. The chart below compares the historical Sharpe Ratios of PEXMX and MMGPX, 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. MMGPX - Drawdown Comparison

The maximum PEXMX drawdown since its inception was -57.82%, smaller than the maximum MMGPX drawdown of -75.38%. Use the drawdown chart below to compare losses from any high point for PEXMX and MMGPX.

Drawdown Indicators

	PEXMX	MMGPX	Difference
Max Drawdown Largest peak-to-trough decline	-57.82%	-75.38%	+17.56%
Max Drawdown (1Y) Largest decline over 1 year	-10.30%	-27.79%	+17.49%
Max Drawdown (3Y) Largest decline over 3 years	-27.01%	-29.27%	+2.26%
Max Drawdown (5Y) Largest decline over 5 years	-36.27%	-72.70%	+36.43%
Max Drawdown (10Y) Largest decline over 10 years	-41.27%	—	—
Current Drawdown Current decline from peak	-2.87%	-40.00%	+37.13%
Average Drawdown Average peak-to-trough decline	-13.57%	-30.34%	+16.77%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.92%	14.02%	-11.10%

Volatility

PEXMX vs. MMGPX - Volatility Comparison

The current volatility for T. Rowe Price Extended Equity Market Index Fund (PEXMX) is 4.92%, while Morgan Stanley Discovery Portfolio (MMGPX) has a volatility of 6.97%. This indicates that PEXMX experiences smaller price fluctuations and is considered to be less risky than MMGPX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	PEXMX	MMGPX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.92%	6.97%	-2.05%
Volatility (6M) Calculated over the trailing 6-month period	13.51%	21.77%	-8.26%
Volatility (1Y) Calculated over the trailing 1-year period	18.13%	28.56%	-10.43%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.56%	39.85%	-17.29%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.22%	35.16%	-12.94%

PEXMX vs. MMGPX - Expense Ratio Comparison

PEXMX has a 0.23% expense ratio, which is higher than MMGPX's 0.04% 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. MMGPX - Dividend Comparison

PEXMX's dividend yield for the trailing twelve months is around 3.51%, while MMGPX has not paid dividends to shareholders.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MMGPX Morgan Stanley Discovery Portfolio	0.00%	0.43%	0.00%	0.00%	125.40%	64.53%	7.93%	15.63%	28.02%	0.00%	0.00%	0.00%
PEXMX T. Rowe Price Extended Equity Market Index Fund	3.51%	4.02%	7.64%	3.64%	7.53%	14.87%	2.99%	8.17%	6.67%	4.50%	5.90%	4.81%

Frequently Asked Questions

Can I hold both PEXMX and MMGPX in my portfolio?

PEXMX and MMGPX have a correlation of 0.74, 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 MMGPX?

MMGPX has higher volatility (6.97%) compared to PEXMX (4.92%). In terms of maximum drawdown, PEXMX dropped -57.82% vs MMGPX's -75.38%.

Which has better risk-adjusted returns?

PEXMX currently has the higher Sharpe Ratio (1.32 vs -0.20), 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.