VIIIX vs. RCKSX
Compare and contrast key facts about Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) and Rock Oak Core Growth Fund (RCKSX).
VIIIX is managed by Vanguard. It was launched on Jul 7, 1997. RCKSX is managed by Oak Associates. It was launched on Dec 31, 2004.
Performance
VIIIX vs. RCKSX - Performance Comparison
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VIIIX vs. RCKSX - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares | -7.06% | 17.87% | 26.29% | 25.79% | -18.14% | 28.69% | 18.41% | 31.48% | -4.41% | 21.82% |
RCKSX Rock Oak Core Growth Fund | 6.05% | 12.99% | 15.12% | 15.57% | -18.09% | 9.96% | 13.75% | 19.05% | -2.14% | 22.69% |
Returns By Period
In the year-to-date period, VIIIX achieves a -7.06% return, which is significantly lower than RCKSX's 6.05% return. Over the past 10 years, VIIIX has outperformed RCKSX with an annualized return of 13.82%, while RCKSX has yielded a comparatively lower 10.21% annualized return.
VIIIX
- 1D
- -0.39%
- 1M
- -7.68%
- YTD
- -7.06%
- 6M
- -4.59%
- 1Y
- 14.44%
- 3Y*
- 17.57%
- 5Y*
- 11.54%
- 10Y*
- 13.82%
RCKSX
- 1D
- -0.32%
- 1M
- -2.56%
- YTD
- 6.05%
- 6M
- 6.54%
- 1Y
- 21.02%
- 3Y*
- 16.53%
- 5Y*
- 5.89%
- 10Y*
- 10.21%
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VIIIX vs. RCKSX - Expense Ratio Comparison
VIIIX has a 0.02% expense ratio, which is lower than RCKSX's 1.25% expense ratio.
Return for Risk
VIIIX vs. RCKSX — Risk / Return Rank
VIIIX
RCKSX
VIIIX vs. RCKSX - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) and Rock Oak Core Growth Fund (RCKSX). 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.
| VIIIX | RCKSX | Difference | |
|---|---|---|---|
Sharpe ratioReturn per unit of total volatility | 0.84 | 1.33 | -0.49 |
Sortino ratioReturn per unit of downside risk | 1.30 | 1.96 | -0.66 |
Omega ratioGain probability vs. loss probability | 1.20 | 1.26 | -0.07 |
Calmar ratioReturn relative to maximum drawdown | 1.06 | 1.76 | -0.70 |
Martin ratioReturn relative to average drawdown | 5.14 | 9.21 | -4.07 |
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month. | |||
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Sharpe Ratios by Period
| VIIIX | RCKSX | Difference | |
|---|---|---|---|
Sharpe Ratio (1Y)Calculated over the trailing 1-year period | 0.84 | 1.33 | -0.49 |
Sharpe Ratio (5Y)Calculated over the trailing 5-year period | 0.69 | 0.38 | +0.31 |
Sharpe Ratio (10Y)Calculated over the trailing 10-year period | 0.77 | 0.58 | +0.19 |
Sharpe Ratio (All Time)Calculated using the full available price history | 0.46 | 0.36 | +0.10 |
Correlation
The correlation between VIIIX and RCKSX is 0.88, which is considered to be high. That indicates a strong positive relationship between their price movements. Having highly-correlated positions in a portfolio may signal a lack of diversification, potentially leading to increased risk during market downturns.
Dividends
VIIIX vs. RCKSX - Dividend Comparison
VIIIX's dividend yield for the trailing twelve months is around 2.90%, less than RCKSX's 5.90% yield.
| TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares | 2.90% | 2.11% | 3.66% | 2.66% | 3.39% | 4.79% | 3.07% | 2.86% | 2.45% | 1.84% | 2.38% | 2.47% |
RCKSX Rock Oak Core Growth Fund | 5.90% | 6.26% | 0.47% | 0.71% | 1.00% | 4.31% | 16.56% | 3.18% | 0.59% | 5.91% | 0.70% | 3.21% |
Drawdowns
VIIIX vs. RCKSX - Drawdown Comparison
The maximum VIIIX drawdown since its inception was -55.18%, roughly equal to the maximum RCKSX drawdown of -57.88%. Use the drawdown chart below to compare losses from any high point for VIIIX and RCKSX.
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Drawdown Indicators
| VIIIX | RCKSX | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -55.18% | -57.88% | +2.70% |
Max Drawdown (1Y)Largest decline over 1 year | -12.12% | -11.29% | -0.83% |
Max Drawdown (5Y)Largest decline over 5 years | -24.50% | -23.50% | -1.00% |
Max Drawdown (10Y)Largest decline over 10 years | -33.79% | -33.10% | -0.69% |
Current DrawdownCurrent decline from peak | -8.90% | -3.25% | -5.65% |
Average DrawdownAverage peak-to-trough decline | -10.07% | -9.58% | -0.49% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 2.49% | 2.15% | +0.34% |
Volatility
VIIIX vs. RCKSX - Volatility Comparison
Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) has a higher volatility of 4.24% compared to Rock Oak Core Growth Fund (RCKSX) at 3.42%. This indicates that VIIIX's price experiences larger fluctuations and is considered to be riskier than RCKSX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| VIIIX | RCKSX | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 4.24% | 3.42% | +0.82% |
Volatility (6M)Calculated over the trailing 6-month period | 9.08% | 8.76% | +0.32% |
Volatility (1Y)Calculated over the trailing 1-year period | 18.13% | 16.37% | +1.76% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 16.85% | 15.77% | +1.08% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 18.02% | 17.58% | +0.44% |