^XSP vs. VIIIX
^XSP (S&P 500 Mini-SPX Options Index) is an index, while VIIIX (Vanguard Institutional Index Fund Institutional Plus Shares) is S&P 500 fund tracking the S&P 500 Index. Over the past 5 years, ^XSP returned 11.99%/yr vs 14.24%/yr for VIIIX. With a 1.00 correlation, they move nearly in lockstep.
Performance
^XSP vs. VIIIX - Performance Comparison
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Returns By Period
In the year-to-date period, ^XSP achieves a 9.16% return, which is significantly lower than VIIIX's 10.19% return.
^XSP
- 1D
- -0.37%
- 1M
- -0.01%
- YTD
- 9.16%
- 6M
- 8.64%
- 1Y
- 25.22%
- 3Y*
- 19.78%
- 5Y*
- 11.99%
- 10Y*
- —
VIIIX
- 1D
- 1.09%
- 1M
- 0.47%
- YTD
- 10.19%
- 6M
- 9.68%
- 1Y
- 27.18%
- 3Y*
- 21.39%
- 5Y*
- 14.24%
- 10Y*
- 15.65%
^XSP vs. VIIIX - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | |
|---|---|---|---|---|---|---|
^XSP S&P 500 Mini-SPX Options Index | 9.16% | 16.39% | 23.31% | 24.23% | -19.44% | 24.04% |
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares | 10.19% | 17.87% | 26.29% | 25.79% | -18.14% | 26.50% |
Correlation
The correlation between ^XSP and VIIIX is 1.00 - these two move nearly in lockstep. At this level, holding both provides almost no diversification benefit. If you already own one, adding the other does little to reduce portfolio risk.
| Correlation | |
|---|---|
Correlation (1Y) Calculated over the trailing 1-year period | 1.00 |
Correlation (3Y) Calculated over the trailing 3-year period | 1.00 |
Correlation (5Y) Calculated over the trailing 5-year period | 1.00 |
Correlation (All Time) Calculated using the full available price history since Mar 1, 2021 | 1.00 |
The correlation between ^XSP and VIIIX has been stable across timeframes, ranging from 1.00 to 1.00 - a consistent structural relationship.
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Return for Risk
^XSP vs. VIIIX — Risk / Return Rank
^XSP
VIIIX
^XSP vs. VIIIX - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for S&P 500 Mini-SPX Options Index (^XSP) and Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX). 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.
Values are calculated on a 1-year rolling basis and updated daily. Risk-adjusted metrics are more stable over longer periods — use the period switch above to explore them.
| ^XSP | VIIIX | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | -0.14 | ||
| Sortino ratioReturn per unit of downside risk | -0.17 | ||
| Omega ratioGain probability vs. loss probability | 1.37 | 1.39 | -0.03 |
| Calmar ratioReturn relative to maximum drawdown | 2.78 | 3.04 | -0.25 |
| Martin ratioReturn relative to average drawdown | 12.44 | 13.74 | -1.30 |
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Drawdowns
^XSP vs. VIIIX - Drawdown Comparison
The maximum ^XSP drawdown since its inception was -25.43%, smaller than the maximum VIIIX drawdown of -55.18%. Use the drawdown chart below to compare losses from any high point for ^XSP and VIIIX.
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Drawdown Indicators
| ^XSP | VIIIX | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -25.43% | -55.18% | +29.75% |
Max Drawdown (1Y)Largest decline over 1 year | -9.10% | -8.90% | -0.20% |
Max Drawdown (3Y)Largest decline over 3 years | -18.90% | -18.75% | -0.15% |
Max Drawdown (5Y)Largest decline over 5 years | -25.43% | -24.50% | -0.93% |
Max Drawdown (10Y)Largest decline over 10 years | — | -33.79% | — |
Current DrawdownCurrent decline from peak | -1.80% | -1.36% | -0.44% |
Average DrawdownAverage peak-to-trough decline | -5.84% | -10.00% | +4.16% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 2.03% | 1.96% | +0.07% |
Volatility
^XSP vs. VIIIX - Volatility Comparison
S&P 500 Mini-SPX Options Index (^XSP) and Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) have volatilities of 4.67% and 4.77%, respectively, indicating that both stocks experience similar levels of price fluctuations. This suggests that the risk associated with both stocks, as measured by volatility, is nearly the same. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| ^XSP | VIIIX | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 4.67% | 4.77% | -0.10% |
Volatility (6M)Calculated over the trailing 6-month period | 9.84% | 9.91% | -0.07% |
Volatility (1Y)Calculated over the trailing 1-year period | 12.50% | 12.47% | +0.03% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 16.99% | 16.99% | 0.00% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 16.81% | 18.10% | -1.29% |
Frequently Asked Questions
With a correlation of 1.00, ^XSP and VIIIX move almost identically. Holding both adds very little diversification - you're essentially doubling your position in the same market segment. Choosing one is usually more capital-efficient.
VIIIX has higher volatility (4.77%) compared to ^XSP (4.67%). In terms of maximum drawdown, ^XSP dropped -25.43% vs VIIIX's -55.18%.
VIIIX currently has the higher Sharpe Ratio (2.17 vs 2.03), 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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