VMGMX vs. POAGX

Last updated Jun 4, 2026

VMGMX (Vanguard Mid-Cap Growth Index Fund Admiral Shares) and POAGX (PrimeCap Odyssey Aggressive Growth Fund) are both Mid Cap Growth Equities funds. Over the past 10 years, VMGMX returned 12.27%/yr vs 15.87%/yr for POAGX. Their correlation of 0.89 suggests significant overlap in exposure. VMGMX charges 0.07%/yr vs 0.65%/yr for POAGX.

Performance

VMGMX vs. POAGX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Mid-Cap Growth Index Fund Admiral Shares (VMGMX) 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, VMGMX achieves a 9.27% return, which is significantly lower than POAGX's 25.05% return. Over the past 10 years, VMGMX has underperformed POAGX with an annualized return of 12.27%, while POAGX has yielded a comparatively higher 15.87% annualized return.

VMGMX

• 1D: 0.96%
• 1M: 6.48%
• YTD: 9.27%
• 6M: 7.33%
• 1Y: 12.39%
• 3Y*: 16.56%
• 5Y*: 7.31%
• 10Y*: 12.27%

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%

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

VMGMX vs. POAGX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VMGMX Vanguard Mid-Cap Growth Index Fund Admiral Shares	9.27%	10.69%	15.65%	23.93%	-28.84%	20.48%	34.45%	33.85%	-5.61%	21.83%
POAGX PrimeCap Odyssey Aggressive Growth Fund	25.05%	28.68%	12.56%	25.02%	-24.25%	4.02%	29.17%	23.52%	-7.10%	33.60%

Correlation

The correlation between VMGMX and POAGX is 0.80, 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	0.80
Correlation (3Y) Calculated over the trailing 3-year period	0.85
Correlation (5Y) Calculated over the trailing 5-year period	0.89
Correlation (10Y) Calculated over the trailing 10-year period	0.88
Correlation (All Time) Calculated using the full available price history since Sep 28, 2011	0.89

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

Return for Risk

VMGMX vs. POAGX — Risk / Return Rank

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

VMGMX

VMGMX Risk / Return Rank: 10
VMGMX Sharpe Ratio Rank: 11
VMGMX Sortino Ratio Rank: 11
VMGMX Omega Ratio Rank: 10
VMGMX Calmar Ratio Rank: 8
VMGMX Martin Ratio Rank: 8

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

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.

VMGMX vs. POAGX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Mid-Cap Growth Index Fund Admiral Shares (VMGMX) 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.

	VMGMX	POAGX	Difference
Sharpe ratio Return per unit of total volatility	0.86	3.07	-2.22
Sortino ratio Return per unit of downside risk	1.28	4.02	-2.74
Omega ratio Gain probability vs. loss probability	1.15	1.52	-0.37
Calmar ratio Return relative to maximum drawdown	0.85	3.71	-2.85
Martin ratio Return relative to average drawdown	2.56	15.14	-12.59
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

VMGMX vs. POAGX - Sharpe Ratio Comparison

The current VMGMX Sharpe Ratio is 0.86, which is lower than the POAGX Sharpe Ratio of 3.07. The chart below compares the historical Sharpe Ratios of VMGMX 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.

Sharpe Ratios by Period

	VMGMX	POAGX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	0.86	3.07	-2.22
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.34	0.47	-0.13
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.59	0.70	-0.11
Sharpe Ratio (All Time) Calculated using the full available price history	0.65	0.64	+0.01

Drawdowns

VMGMX vs. POAGX - Drawdown Comparison

The maximum VMGMX drawdown since its inception was -37.17%, smaller than the maximum POAGX drawdown of -55.77%. Use the drawdown chart below to compare losses from any high point for VMGMX and POAGX.

Drawdown Indicators

	VMGMX	POAGX	Difference
Max Drawdown Largest peak-to-trough decline	-37.17%	-55.77%	+18.60%
Max Drawdown (1Y) Largest decline over 1 year	-15.95%	-16.87%	+0.92%
Max Drawdown (3Y) Largest decline over 3 years	-21.65%	-24.73%	+3.08%
Max Drawdown (5Y) Largest decline over 5 years	-37.17%	-38.80%	+1.63%
Max Drawdown (10Y) Largest decline over 10 years	-37.17%	-38.80%	+1.63%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-7.02%	-9.54%	+2.52%
Ulcer Index Depth and duration of drawdowns from previous peaks	5.31%	4.12%	+1.19%

Volatility

VMGMX vs. POAGX - Volatility Comparison

The current volatility for Vanguard Mid-Cap Growth Index Fund Admiral Shares (VMGMX) is 4.27%, while PrimeCap Odyssey Aggressive Growth Fund (POAGX) has a volatility of 7.94%. This indicates that VMGMX 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

	VMGMX	POAGX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.27%	7.94%	-3.67%
Volatility (6M) Calculated over the trailing 6-month period	12.46%	16.25%	-3.79%
Volatility (1Y) Calculated over the trailing 1-year period	15.90%	20.35%	-4.45%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.42%	22.90%	-1.48%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	20.99%	22.90%	-1.91%

VMGMX vs. POAGX - Expense Ratio Comparison

VMGMX has a 0.07% expense ratio, which is lower than POAGX's 0.65% expense ratio.

Dividends

VMGMX vs. POAGX - Dividend Comparison

VMGMX's dividend yield for the trailing twelve months is around 0.60%, less than POAGX's 10.60% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
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%
VMGMX Vanguard Mid-Cap Growth Index Fund Admiral Shares	0.60%	0.64%	0.67%	0.71%	0.78%	0.34%	0.56%	0.78%	0.84%	0.72%	0.81%	0.82%

Frequently Asked Questions

Can I hold both VMGMX and POAGX in my portfolio?

VMGMX 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, VMGMX or POAGX?

POAGX has higher volatility (7.94%) compared to VMGMX (4.27%). In terms of maximum drawdown, VMGMX dropped -37.17% vs POAGX's -55.77%.

Which has better risk-adjusted returns?

POAGX currently has the higher Sharpe Ratio (3.07 vs 0.86), 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.