POAGX vs. VIMSX

Last updated Jun 3, 2026

POAGX (PrimeCap Odyssey Aggressive Growth Fund) and VIMSX (Vanguard Mid Cap Index Fund) are both mutual funds - POAGX is a Mid Cap Growth Equities fund managed by PRIMECAP Odyssey Funds, while VIMSX is a Mid Cap Blend Equities fund managed by Vanguard. Over the past 10 years, POAGX returned 15.82%/yr vs 11.30%/yr for VIMSX. Their correlation of 0.87 suggests significant overlap in exposure. POAGX charges 0.65%/yr vs 0.17%/yr for VIMSX.

Performance

POAGX vs. VIMSX - Performance Comparison

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

Returns By Period

In the year-to-date period, POAGX achieves a 24.45% return, which is significantly higher than VIMSX's 9.49% return. Over the past 10 years, POAGX has outperformed VIMSX with an annualized return of 15.82%, while VIMSX has yielded a comparatively lower 11.30% annualized return.

POAGX

• 1D: 0.84%
• 1M: 17.17%
• YTD: 24.45%
• 6M: 27.48%
• 1Y: 61.42%
• 3Y*: 25.36%
• 5Y*: 10.44%
• 10Y*: 15.82%

VIMSX

• 1D: 0.30%
• 1M: 2.53%
• YTD: 9.49%
• 6M: 10.00%
• 1Y: 18.55%
• 3Y*: 16.18%
• 5Y*: 7.58%
• 10Y*: 11.30%

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

POAGX vs. VIMSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
POAGX PrimeCap Odyssey Aggressive Growth Fund	24.45%	28.68%	12.56%	25.02%	-24.25%	4.02%	29.17%	23.52%	-7.10%	33.60%
VIMSX Vanguard Mid Cap Index Fund	9.49%	11.08%	14.52%	16.40%	-18.80%	24.36%	18.04%	30.85%	-9.35%	19.12%

Correlation

The correlation between POAGX and VIMSX 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	0.84
Correlation (10Y) Calculated over the trailing 10-year period	0.85
Correlation (All Time) Calculated using the full available price history since Nov 3, 2004	0.87

The correlation between POAGX and VIMSX shifts across timeframes, from 0.74 (1 year) to 0.87 (all time), reflecting how their relationship changes across market environments.

Return for Risk

POAGX vs. VIMSX — Risk / Return Rank

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

POAGX

POAGX Risk / Return Rank: 84
POAGX Sharpe Ratio Rank: 93
POAGX Sortino Ratio Rank: 85
POAGX Omega Ratio Rank: 79
POAGX Calmar Ratio Rank: 80
POAGX Martin Ratio Rank: 80

VIMSX

VIMSX Risk / Return Rank: 32
VIMSX Sharpe Ratio Rank: 28
VIMSX Sortino Ratio Rank: 27
VIMSX Omega Ratio Rank: 25
VIMSX Calmar Ratio Rank: 37
VIMSX Martin Ratio Rank: 41

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. VIMSX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for PrimeCap Odyssey Aggressive Growth Fund (POAGX) and Vanguard Mid Cap Index Fund (VIMSX). 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	VIMSX	Difference
Sharpe ratio Return per unit of total volatility	3.11	1.54	+1.57
Sortino ratio Return per unit of downside risk	4.06	2.21	+1.85
Omega ratio Gain probability vs. loss probability	1.52	1.27	+0.25
Calmar ratio Return relative to maximum drawdown	3.68	2.34	+1.34
Martin ratio Return relative to average drawdown	15.09	8.91	+6.18
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. VIMSX - Sharpe Ratio Comparison

The current POAGX Sharpe Ratio is 3.11, which is higher than the VIMSX Sharpe Ratio of 1.54. The chart below compares the historical Sharpe Ratios of POAGX and VIMSX, 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	VIMSX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	3.11	1.54	+1.57
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.46	0.43	+0.03
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.69	0.60	+0.09
Sharpe Ratio (All Time) Calculated using the full available price history	0.64	0.48	+0.16

Drawdowns

POAGX vs. VIMSX - Drawdown Comparison

The maximum POAGX drawdown since its inception was -55.77%, smaller than the maximum VIMSX drawdown of -58.96%. Use the drawdown chart below to compare losses from any high point for POAGX and VIMSX.

Drawdown Indicators

	POAGX	VIMSX	Difference
Max Drawdown Largest peak-to-trough decline	-55.77%	-58.96%	+3.19%
Max Drawdown (1Y) Largest decline over 1 year	-16.87%	-8.14%	-8.73%
Max Drawdown (3Y) Largest decline over 3 years	-24.73%	-19.31%	-5.42%
Max Drawdown (5Y) Largest decline over 5 years	-38.80%	-27.63%	-11.17%
Max Drawdown (10Y) Largest decline over 10 years	-38.80%	-39.29%	+0.49%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-9.54%	-8.08%	-1.46%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.12%	2.14%	+1.98%

Volatility

POAGX vs. VIMSX - Volatility Comparison

PrimeCap Odyssey Aggressive Growth Fund (POAGX) has a higher volatility of 7.93% compared to Vanguard Mid Cap Index Fund (VIMSX) at 2.89%. This indicates that POAGX's price experiences larger fluctuations and is considered to be riskier than VIMSX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	POAGX	VIMSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	7.93%	2.89%	+5.04%
Volatility (6M) Calculated over the trailing 6-month period	16.25%	9.26%	+6.99%
Volatility (1Y) Calculated over the trailing 1-year period	20.39%	12.29%	+8.10%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.90%	17.64%	+5.26%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.90%	18.92%	+3.98%

POAGX vs. VIMSX - Expense Ratio Comparison

POAGX has a 0.65% expense ratio, which is higher than VIMSX's 0.17% expense ratio.

Dividends

POAGX vs. VIMSX - Dividend Comparison

POAGX's dividend yield for the trailing twelve months is around 10.65%, more than VIMSX's 1.25% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
POAGX PrimeCap Odyssey Aggressive Growth Fund	10.65%	13.25%	9.90%	5.54%	10.78%	5.93%	7.84%	5.33%	7.82%	0.86%	16.63%	12.52%
VIMSX Vanguard Mid Cap Index Fund	1.25%	1.03%	1.37%	1.39%	1.46%	1.00%	1.34%	1.37%	1.68%	1.24%	1.34%	1.33%

Frequently Asked Questions

Can I hold both POAGX and VIMSX in my portfolio?

POAGX and VIMSX 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, POAGX or VIMSX?

POAGX has higher volatility (7.93%) compared to VIMSX (2.89%). In terms of maximum drawdown, POAGX dropped -55.77% vs VIMSX's -58.96%.

Which has better risk-adjusted returns?

POAGX currently has the higher Sharpe Ratio (3.11 vs 1.54), 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.