FMDGX vs. POAGX

Last updated Jun 26, 2026

FMDGX (Fidelity Mid Cap Growth Index Fund) and POAGX (PrimeCap Odyssey Aggressive Growth Fund) are both Mid Cap Growth Equities funds. Over the past 5 years, FMDGX returned 5.28%/yr vs 9.59%/yr for POAGX. Their correlation of 0.89 suggests significant overlap in exposure. FMDGX charges 0.05%/yr vs 0.65%/yr for POAGX.

Performance

FMDGX vs. POAGX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Fidelity Mid Cap Growth Index Fund (FMDGX) and PrimeCap Odyssey Aggressive Growth Fund (POAGX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, FMDGX achieves a 3.45% return, which is significantly lower than POAGX's 24.11% return.

FMDGX

• 1D: 0.97%
• 1M: 0.53%
• YTD: 3.45%
• 6M: 1.23%
• 1Y: 3.73%
• 3Y*: 15.55%
• 5Y*: 5.28%
• 10Y*: —

POAGX

• 1D: 0.32%
• 1M: 3.00%
• YTD: 24.11%
• 6M: 21.56%
• 1Y: 54.65%
• 3Y*: 25.07%
• 5Y*: 9.59%
• 10Y*: 16.39%

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

FMDGX vs. POAGX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019
FMDGX Fidelity Mid Cap Growth Index Fund	3.45%	8.60%	22.03%	25.79%	-26.67%	12.67%	34.84%	4.63%
POAGX PrimeCap Odyssey Aggressive Growth Fund	24.11%	28.68%	12.56%	25.02%	-24.25%	4.02%	29.17%	3.72%

Correlation

The correlation between FMDGX and POAGX is 0.80, 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	0.80
Correlation (3Y) Calculated over the trailing 3-year period	0.85
Correlation (5Y) Calculated over the trailing 5-year period	0.89
Correlation (All Time) Calculated using the full available price history since Jul 17, 2019	0.89

The correlation between FMDGX and POAGX has been stable across timeframes, ranging from 0.80 to 0.89 - a consistent structural relationship.

Return for Risk

FMDGX vs. POAGX — Risk / Return Rank

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

FMDGX

FMDGX Risk / Return Rank: 5
FMDGX Sharpe Ratio Rank: 5
FMDGX Sortino Ratio Rank: 5
FMDGX Omega Ratio Rank: 5
FMDGX Calmar Ratio Rank: 5
FMDGX Martin Ratio Rank: 5

POAGX

POAGX Risk / Return Rank: 82
POAGX Sharpe Ratio Rank: 86
POAGX Sortino Ratio Rank: 80
POAGX Omega Ratio Rank: 78
POAGX Calmar Ratio Rank: 81
POAGX Martin Ratio Rank: 83

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.

FMDGX vs. POAGX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity Mid Cap Growth Index Fund (FMDGX) and PrimeCap Odyssey Aggressive Growth Fund (POAGX). 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.

	FMDGX	POAGX	Difference
Sharpe ratio: Return per unit of total volatility	0.17	2.45	-2.28
Sortino ratio: Return per unit of downside risk	0.37	3.21	-2.85
Omega ratio: Gain probability vs. loss probability	1.04	1.42	-0.38
Calmar ratio: Return relative to maximum drawdown	0.20	3.26	-3.06
Martin ratio: Return relative to average drawdown	0.58	13.09	-12.51

FMDGX vs. POAGX - Sharpe Ratio Comparison

The current FMDGX Sharpe Ratio is 0.17, which is lower than the POAGX Sharpe Ratio of 2.45. The chart below compares the historical Sharpe Ratios of FMDGX and POAGX, 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

FMDGX vs. POAGX - Drawdown Comparison

The maximum FMDGX drawdown since its inception was -38.59%, smaller than the maximum POAGX drawdown of -55.77%. Use the drawdown chart below to compare losses from any high point for FMDGX and POAGX.

Drawdown Indicators

	FMDGX	POAGX	Difference
Max Drawdown Largest peak-to-trough decline	-38.59%	-55.77%	+17.18%
Max Drawdown (1Y) Largest decline over 1 year	-14.75%	-16.87%	+2.12%
Max Drawdown (3Y) Largest decline over 3 years	-25.30%	-24.73%	-0.57%
Max Drawdown (5Y) Largest decline over 5 years	-38.59%	-38.80%	+0.21%
Max Drawdown (10Y) Largest decline over 10 years	—	-38.80%	—
Current Drawdown Current decline from peak	-2.43%	-3.13%	+0.70%
Average Drawdown Average peak-to-trough decline	-11.13%	-9.52%	-1.61%
Ulcer Index Depth and duration of drawdowns from previous peaks	5.10%	4.19%	+0.91%

Volatility

FMDGX vs. POAGX - Volatility Comparison

The current volatility for Fidelity Mid Cap Growth Index Fund (FMDGX) is 5.85%, while PrimeCap Odyssey Aggressive Growth Fund (POAGX) has a volatility of 11.07%. This indicates that FMDGX experiences smaller price fluctuations and is considered to be less risky than POAGX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FMDGX	POAGX	Difference
Volatility (1M) Calculated over the trailing 1-month period	5.85%	11.07%	-5.22%
Volatility (6M) Calculated over the trailing 6-month period	13.42%	18.68%	-5.26%
Volatility (1Y) Calculated over the trailing 1-year period	17.10%	22.48%	-5.38%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.46%	23.29%	-0.83%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	24.30%	23.04%	+1.26%

FMDGX vs. POAGX - Expense Ratio Comparison

FMDGX has a 0.05% expense ratio, which is lower than POAGX's 0.65% expense ratio.

Dividends

FMDGX vs. POAGX - Dividend Comparison

FMDGX's dividend yield for the trailing twelve months is around 1.79%, less than POAGX's 10.68% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FMDGX Fidelity Mid Cap Growth Index Fund	1.79%	1.85%	0.47%	0.63%	0.81%	6.43%	0.36%	0.29%	0.00%	0.00%	0.00%	0.00%
POAGX PrimeCap Odyssey Aggressive Growth Fund	10.68%	13.25%	9.90%	5.54%	10.78%	5.93%	7.84%	5.33%	7.82%	0.86%	16.63%	12.52%

Frequently Asked Questions

Can I hold both FMDGX and POAGX in my portfolio?

FMDGX and POAGX have a correlation of 0.80, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, FMDGX or POAGX?

POAGX has higher volatility (11.07%) compared to FMDGX (5.85%). In terms of maximum drawdown, FMDGX dropped -38.59% vs POAGX's -55.77%.

Which has better risk-adjusted returns?

POAGX currently has the higher Sharpe Ratio (2.45 vs 0.17), 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.