POAGX vs. FMDGX

Last updated Jun 4, 2026

POAGX (PrimeCap Odyssey Aggressive Growth Fund) and FMDGX (Fidelity Mid Cap Growth Index Fund) are both Mid Cap Growth Equities funds. Over the past 5 years, POAGX returned 10.82%/yr vs 7.23%/yr for FMDGX. Their correlation of 0.89 suggests significant overlap in exposure. POAGX charges 0.65%/yr vs 0.05%/yr for FMDGX.

Performance

POAGX vs. FMDGX - Performance Comparison

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

Returns By Period

In the year-to-date period, POAGX achieves a 25.05% return, which is significantly higher than FMDGX's 4.88% return.

POAGX

• 1D: 0.48%
• 1M: 16.75%
• YTD: 25.05%
• 6M: 26.41%
• 1Y: 60.37%
• 3Y*: 25.56%
• 5Y*: 10.82%
• 10Y*: 15.87%

FMDGX

• 1D: -0.22%
• 1M: 5.21%
• YTD: 4.88%
• 6M: 3.96%
• 1Y: 6.81%
• 3Y*: 16.42%
• 5Y*: 7.23%
• 10Y*: —

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

POAGX vs. FMDGX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019
POAGX PrimeCap Odyssey Aggressive Growth Fund	25.05%	28.68%	12.56%	25.02%	-24.25%	4.02%	29.17%	3.47%
FMDGX Fidelity Mid Cap Growth Index Fund	4.88%	8.60%	22.03%	25.79%	-26.67%	12.67%	34.84%	4.63%

Correlation

The correlation between POAGX and FMDGX is 0.81, 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	0.81
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 18, 2019	0.89

The correlation between POAGX and FMDGX has been stable across timeframes, ranging from 0.81 to 0.89 - a consistent structural relationship.

Return for Risk

POAGX vs. FMDGX — Risk / Return Rank

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

POAGX

POAGX Risk / Return Rank: 83
POAGX Sharpe Ratio Rank: 92
POAGX Sortino Ratio Rank: 85
POAGX Omega Ratio Rank: 79
POAGX Calmar Ratio Rank: 81
POAGX Martin Ratio Rank: 81

FMDGX

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

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.

POAGX vs. FMDGX - Risk-Adjusted Trends Comparison

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

	POAGX	FMDGX	Difference
Sharpe ratio Return per unit of total volatility	3.07	0.49	+2.59
Sortino ratio Return per unit of downside risk	4.02	0.80	+3.22
Omega ratio Gain probability vs. loss probability	1.52	1.09	+0.43
Calmar ratio Return relative to maximum drawdown	3.71	0.54	+3.16
Martin ratio Return relative to average drawdown	15.14	1.58	+13.56
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

POAGX vs. FMDGX - Sharpe Ratio Comparison

The current POAGX Sharpe Ratio is 3.07, which is higher than the FMDGX Sharpe Ratio of 0.49. The chart below compares the historical Sharpe Ratios of POAGX and FMDGX, 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

	POAGX	FMDGX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	3.07	0.49	+2.59
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.47	0.32	+0.15
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.70	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.64	0.45	+0.19

Drawdowns

POAGX vs. FMDGX - Drawdown Comparison

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

Drawdown Indicators

	POAGX	FMDGX	Difference
Max Drawdown Largest peak-to-trough decline	-55.77%	-38.59%	-17.18%
Max Drawdown (1Y) Largest decline over 1 year	-16.87%	-14.75%	-2.12%
Max Drawdown (3Y) Largest decline over 3 years	-24.73%	-25.30%	+0.57%
Max Drawdown (5Y) Largest decline over 5 years	-38.80%	-38.59%	-0.21%
Max Drawdown (10Y) Largest decline over 10 years	-38.80%	—	—
Current Drawdown Current decline from peak	0.00%	-1.09%	+1.09%
Average Drawdown Average peak-to-trough decline	-9.54%	-11.21%	+1.67%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.12%	5.05%	-0.93%

Volatility

POAGX vs. FMDGX - Volatility Comparison

PrimeCap Odyssey Aggressive Growth Fund (POAGX) has a higher volatility of 7.94% compared to Fidelity Mid Cap Growth Index Fund (FMDGX) at 3.52%. This indicates that POAGX's price experiences larger fluctuations and is considered to be riskier than FMDGX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	POAGX	FMDGX	Difference
Volatility (1M) Calculated over the trailing 1-month period	7.94%	3.52%	+4.42%
Volatility (6M) Calculated over the trailing 6-month period	16.25%	12.64%	+3.61%
Volatility (1Y) Calculated over the trailing 1-year period	20.35%	16.46%	+3.89%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.90%	22.37%	+0.53%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.90%	24.32%	-1.42%

POAGX vs. FMDGX - Expense Ratio Comparison

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

Dividends

POAGX vs. FMDGX - Dividend Comparison

POAGX's dividend yield for the trailing twelve months is around 10.60%, more than FMDGX's 1.77% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FMDGX Fidelity Mid Cap Growth Index Fund	1.77%	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	10.60%	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 POAGX and FMDGX in my portfolio?

POAGX and FMDGX have a correlation of 0.81, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, POAGX or FMDGX?

POAGX has higher volatility (7.94%) compared to FMDGX (3.52%). In terms of maximum drawdown, POAGX dropped -55.77% vs FMDGX's -38.59%.

Which has better risk-adjusted returns?

POAGX currently has the higher Sharpe Ratio (3.07 vs 0.49), 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.