PRDMX vs. FSMAX

Last updated Jul 14, 2026

PRDMX (T. Rowe Price Diversified Mid Cap Growth Fund) and FSMAX (Fidelity Extended Market Index Fund) are both mutual funds - PRDMX is a Mid Cap Growth Equities fund managed by T. Rowe Price, while FSMAX is a Mid Cap Blend Equities fund tracking the Dow Jones U.S. Completion Total Stock Market Index. Over the past 10 years, PRDMX returned 12.75%/yr vs 11.95%/yr for FSMAX. Their correlation of 0.93 suggests significant overlap in exposure. PRDMX charges 0.79%/yr vs 0.04%/yr for FSMAX.

Performance

PRDMX vs. FSMAX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in T. Rowe Price Diversified Mid Cap Growth Fund (PRDMX) and Fidelity Extended Market Index Fund (FSMAX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, PRDMX achieves a 5.01% return, which is significantly lower than FSMAX's 15.91% return. Over the past 10 years, PRDMX has outperformed FSMAX with an annualized return of 12.75%, while FSMAX has yielded a comparatively lower 11.95% annualized return.

PRDMX

• 1D: -0.75%
• 1M: 1.38%
• 6M: 1.45%
• YTD: 5.01%
• 1Y: 5.93%
• 3Y*: 14.23%
• 5Y*: 5.99%
• 10Y*: 12.75%

FSMAX

• 1D: -0.57%
• 1M: 1.32%
• 6M: 10.50%
• YTD: 15.91%
• 1Y: 24.38%
• 3Y*: 18.11%
• 5Y*: 6.36%
• 10Y*: 11.95%

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

PRDMX vs. FSMAX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PRDMX T. Rowe Price Diversified Mid Cap Growth Fund	5.01%	10.30%	23.77%	20.75%	-24.65%	13.56%	31.82%	37.91%	-3.15%	24.66%
FSMAX Fidelity Extended Market Index Fund	15.91%	11.40%	16.99%	25.36%	-26.44%	12.41%	32.28%	28.01%	-9.44%	18.04%

Correlation

The correlation between PRDMX and FSMAX is 0.93, 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	0.93
Correlation (3Y) Calculated over the trailing 3-year period	0.91
Correlation (5Y) Calculated over the trailing 5-year period	0.93
Correlation (10Y) Calculated over the trailing 10-year period	0.92
Correlation (All Time) Calculated using the full available price history since Sep 8, 2011	0.93

The correlation between PRDMX and FSMAX has been stable across timeframes, ranging from 0.91 to 0.93 - a consistent structural relationship.

Return for Risk

PRDMX vs. FSMAX — Risk / Return Rank

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

PRDMX

PRDMX Risk / Return Rank: 6
PRDMX Sharpe Ratio Rank: 6
PRDMX Sortino Ratio Rank: 6
PRDMX Omega Ratio Rank: 6
PRDMX Calmar Ratio Rank: 6
PRDMX Martin Ratio Rank: 7

FSMAX

FSMAX Risk / Return Rank: 41
FSMAX Sharpe Ratio Rank: 35
FSMAX Sortino Ratio Rank: 34
FSMAX Omega Ratio Rank: 32
FSMAX Calmar Ratio Rank: 54
FSMAX Martin Ratio Rank: 47

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.

PRDMX vs. FSMAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for T. Rowe Price Diversified Mid Cap Growth Fund (PRDMX) and Fidelity Extended Market Index Fund (FSMAX). 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.

	PRDMX	FSMAX	Difference
Sharpe ratio: Return per unit of total volatility	0.28	1.30	-1.02
Sortino ratio: Return per unit of downside risk	0.52	1.89	-1.36
Omega ratio: Gain probability vs. loss probability	1.06	1.23	-0.17
Calmar ratio: Return relative to maximum drawdown	0.35	2.26	-1.90
Martin ratio: Return relative to average drawdown	1.10	7.89	-6.79

PRDMX vs. FSMAX - Sharpe Ratio Comparison

The current PRDMX Sharpe Ratio is 0.28, which is lower than the FSMAX Sharpe Ratio of 1.30. The chart below compares the historical Sharpe Ratios of PRDMX and FSMAX, 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

PRDMX vs. FSMAX - Drawdown Comparison

The maximum PRDMX drawdown since its inception was -57.57%, which is greater than FSMAX's maximum drawdown of -50.55%. Use the drawdown chart below to compare losses from any high point for PRDMX and FSMAX.

Drawdown Indicators

	PRDMX	FSMAX	Difference
Max Drawdown Largest peak-to-trough decline	-57.57%	-50.55%	-7.02%
Max Drawdown (1Y) Largest decline over 1 year	-14.15%	-10.26%	-3.89%
Max Drawdown (3Y) Largest decline over 3 years	-25.06%	-26.82%	+1.76%
Max Drawdown (5Y) Largest decline over 5 years	-35.69%	-36.31%	+0.62%
Max Drawdown (10Y) Largest decline over 10 years	-35.91%	-50.55%	+14.64%
Current Drawdown Current decline from peak	-2.95%	-2.02%	-0.93%
Average Drawdown Average peak-to-trough decline	-8.41%	-12.09%	+3.68%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.54%	2.93%	+1.61%

Volatility

PRDMX vs. FSMAX - Volatility Comparison

T. Rowe Price Diversified Mid Cap Growth Fund (PRDMX) has a higher volatility of 6.42% compared to Fidelity Extended Market Index Fund (FSMAX) at 5.14%. This indicates that PRDMX's price experiences larger fluctuations and is considered to be riskier than FSMAX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	PRDMX	FSMAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.42%	5.14%	+1.28%
Volatility (6M) Calculated over the trailing 6-month period	14.06%	13.25%	+0.81%
Volatility (1Y) Calculated over the trailing 1-year period	17.71%	17.79%	-0.08%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.96%	22.43%	-0.47%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.37%	30.21%	-8.84%

PRDMX vs. FSMAX - Expense Ratio Comparison

PRDMX has a 0.79% expense ratio, which is higher than FSMAX's 0.04% expense ratio.

Dividends

PRDMX vs. FSMAX - Dividend Comparison

PRDMX's dividend yield for the trailing twelve months is around 7.38%, more than FSMAX's 0.49% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FSMAX Fidelity Extended Market Index Fund	0.49%	0.57%	0.48%	1.17%	1.90%	7.49%	2.14%	4.30%	6.09%	5.44%	4.85%	6.34%
PRDMX T. Rowe Price Diversified Mid Cap Growth Fund	7.38%	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 PRDMX and FSMAX in my portfolio?

With a correlation of 0.93, PRDMX and FSMAX 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, PRDMX or FSMAX?

PRDMX has higher volatility (6.42%) compared to FSMAX (5.14%). In terms of maximum drawdown, PRDMX dropped -57.57% vs FSMAX's -50.55%.

Which has better risk-adjusted returns?

FSMAX currently has the higher Sharpe Ratio (1.30 vs 0.28), 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.