VIIIX vs. VFISX
VIIIX (Vanguard Institutional Index Fund Institutional Plus Shares) and VFISX (Vanguard Short-Term Treasury Fund Investor Shares) are both mutual funds - VIIIX is a S&P 500 fund tracking the S&P 500 Index, while VFISX is a Government Bonds fund managed by Vanguard. Over the past 10 years, VIIIX returned 15.32%/yr vs 1.58%/yr for VFISX. At a correlation of -0.16, they often move in opposite directions. VIIIX charges 0.02%/yr vs 0.20%/yr for VFISX.
Performance
VIIIX vs. VFISX - Performance Comparison
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Returns By Period
In the year-to-date period, VIIIX achieves a 8.42% return, which is significantly higher than VFISX's 0.19% return. Over the past 10 years, VIIIX has outperformed VFISX with an annualized return of 15.32%, while VFISX has yielded a comparatively lower 1.58% annualized return.
VIIIX
- 1D
- -2.63%
- 1M
- -0.08%
- YTD
- 8.42%
- 6M
- 8.48%
- 1Y
- 24.54%
- 3Y*
- 21.94%
- 5Y*
- 13.54%
- 10Y*
- 15.32%
VFISX
- 1D
- -0.20%
- 1M
- -0.29%
- YTD
- 0.19%
- 6M
- 0.60%
- 1Y
- 3.48%
- 3Y*
- 3.94%
- 5Y*
- 1.36%
- 10Y*
- 1.58%
VIIIX vs. VFISX - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares | 8.42% | 17.87% | 26.29% | 25.79% | -18.14% | 28.69% | 18.41% | 31.48% | -4.41% | 21.82% |
VFISX Vanguard Short-Term Treasury Fund Investor Shares | 0.19% | 5.36% | 3.75% | 3.54% | -4.71% | -0.88% | 3.95% | 3.60% | 1.36% | 0.38% |
Correlation
The correlation between VIIIX and VFISX is 0.19, which is low. Their price movements are largely independent, making them effective diversification partners.
| Correlation | |
|---|---|
Correlation (1Y) Calculated over the trailing 1-year period | 0.19 |
Correlation (3Y) Calculated over the trailing 3-year period | 0.10 |
Correlation (5Y) Calculated over the trailing 5-year period | 0.07 |
Correlation (10Y) Calculated over the trailing 10-year period | -0.05 |
Correlation (All Time) Calculated using the full available price history since Jul 8, 1997 | -0.16 |
The correlation between VIIIX and VFISX shifts across timeframes, from -0.16 (all time) to 0.19 (1 year), reflecting how their relationship changes across market environments.
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Return for Risk
VIIIX vs. VFISX — Risk / Return Rank
VIIIX
VFISX
VIIIX vs. VFISX - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) and Vanguard Short-Term Treasury Fund Investor Shares (VFISX). 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 | VFISX | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | +0.58 | ||
| Sortino ratioReturn per unit of downside risk | +0.22 | ||
| Omega ratioGain probability vs. loss probability | 1.39 | 1.32 | +0.07 |
| Calmar ratioReturn relative to maximum drawdown | 2.92 | 2.26 | +0.65 |
| Martin ratioReturn relative to average drawdown | 13.57 | 7.48 | +6.09 |
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 | VFISX | Difference | |
|---|---|---|---|
Sharpe Ratio (1Y)Calculated over the trailing 1-year period | 2.13 | 1.55 | +0.58 |
Sharpe Ratio (5Y)Calculated over the trailing 5-year period | 0.80 | 0.51 | +0.29 |
Sharpe Ratio (10Y)Calculated over the trailing 10-year period | 0.85 | 0.75 | +0.10 |
Sharpe Ratio (All Time)Calculated using the full available price history | 0.49 | 1.53 | -1.04 |
Drawdowns
VIIIX vs. VFISX - Drawdown Comparison
The maximum VIIIX drawdown since its inception was -55.18%, which is greater than VFISX's maximum drawdown of -6.86%. Use the drawdown chart below to compare losses from any high point for VIIIX and VFISX.
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Drawdown Indicators
| VIIIX | VFISX | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -55.18% | -6.86% | -48.32% |
Max Drawdown (1Y)Largest decline over 1 year | -8.90% | -1.40% | -7.50% |
Max Drawdown (3Y)Largest decline over 3 years | -18.75% | -1.40% | -17.35% |
Max Drawdown (5Y)Largest decline over 5 years | -24.50% | -6.86% | -17.64% |
Max Drawdown (10Y)Largest decline over 10 years | -33.79% | -6.86% | -26.93% |
Current DrawdownCurrent decline from peak | -2.94% | -0.79% | -2.15% |
Average DrawdownAverage peak-to-trough decline | -10.01% | -0.65% | -9.36% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 1.91% | 0.42% | +1.49% |
Volatility
VIIIX vs. VFISX - Volatility Comparison
Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) has a higher volatility of 3.81% compared to Vanguard Short-Term Treasury Fund Investor Shares (VFISX) at 0.58%. This indicates that VIIIX's price experiences larger fluctuations and is considered to be riskier than VFISX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| VIIIX | VFISX | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 3.81% | 0.58% | +3.23% |
Volatility (6M)Calculated over the trailing 6-month period | 9.41% | 1.50% | +7.91% |
Volatility (1Y)Calculated over the trailing 1-year period | 12.19% | 2.06% | +10.13% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 16.93% | 2.67% | +14.26% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 18.08% | 2.11% | +15.97% |
VIIIX vs. VFISX - Expense Ratio Comparison
VIIIX has a 0.02% expense ratio, which is lower than VFISX's 0.20% expense ratio. Despite the difference, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.
Dividends
VIIIX vs. VFISX - Dividend Comparison
VIIIX's dividend yield for the trailing twelve months is around 2.48%, less than VFISX's 3.76% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
VFISX Vanguard Short-Term Treasury Fund Investor Shares | 3.76% | 3.89% | 4.38% | 3.95% | 1.93% | 0.52% | 2.20% | 2.39% | 2.10% | 1.15% | 1.18% | 0.83% |
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares | 2.48% | 2.11% | 3.66% | 2.66% | 3.39% | 4.79% | 3.07% | 2.86% | 2.45% | 1.84% | 2.38% | 2.47% |
Frequently Asked Questions
VIIIX and VFISX have a correlation of 0.19, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.
VIIIX has higher volatility (3.81%) compared to VFISX (0.58%). In terms of maximum drawdown, VIIIX dropped -55.18% vs VFISX's -6.86%.
VIIIX currently has the higher Sharpe Ratio (2.13 vs 1.55), 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.
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