Registry rank 11 · Portfolio as of 2026-03-31
VANGUARD INSTITUTIONAL INDEX FUND
VIIIX (Vanguard Institutional Index Fund) · VINIX (Vanguard Institutional Index Fund)
The verdict
What the numbers say
This fund holds essentially the same portfolio as Vanguard 500 Index Fund but charges $20 a year per $100,000 instead of $10 — about $504 more over 20 years.
Data provenance
Run 363649da-fcfb-4007-87ef-de06de7710ca; method closet-index@2.0.0; fund accession 0000862084-26-000094; comparison periods and expense-filing links appear with their figures. Machine capture time: 2026-07-29T14:22:09.616Z.
Computed rule checks
0 warnings · 3 checks clear · 0 unavailable
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· Rule 1
The fund’s filed benchmark and its closest approved index control point to the same comparison.
Methodology rule · visual rules si-visual-explainers@1.0.0
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· Rule 2
The existing same-index active-share and fee rule does not issue a closet-index warning. This is not a rating.
Methodology rule · visual rules si-visual-explainers@1.0.0
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· Rule 3
Over the 20-year window from 2006-07-31 to 2026-07-29, annualized fund-minus-index tracking difference was 0.10% against a 0.02% filed fee. The annualized lag did not exceed the fee.
Computed on licensed market-return history · filed fee as of 2025-12-31
Methodology rule · visual rules si-visual-explainers@1.0.0
Filed fees in dollars
SEC-convention illustration
Computed from SEC filings
Assumptions for each dollar figure: $100,000 starting amount · 5.0% annual return · annual compounding · fees deducted annually · 0.01% computed index-control baseline. Methodology.
| Share class and filing | 10 years | 20 years | 30 years |
|---|---|---|---|
| VIIIX0.02% · SEC expense filing · as of 2025-12-31 | $155 | $504 | $1,230 |
| VINIX0.03% · SEC expense filing · as of 2025-12-31 | $310 | $1,007 | $2,456 |
Real trailing windows
Computed on licensed market-return history
Trailing windows use iShares Core S&P 500 ETF (IVV) adjusted-close total-return history through 2026-07-29 and the same filed index-control fee baseline as the convention table. Methodology.
| Share class and filing | 10 years | 20 years | 30 years |
|---|---|---|---|
| VIIIXFiled fee as of 2025-12-31 | $348Computed on licensed market-return history 2016-07-29 to 2026-07-29 · proxy return 14.88% annualized | $1,496Computed on licensed market-return history 2006-07-31 to 2026-07-29 · proxy return 11.19% annualized | Proxy history begins 2000 — no full 30-year window |
| VINIXFiled fee as of 2025-12-31 | $696Computed on licensed market-return history 2016-07-29 to 2026-07-29 · proxy return 14.88% annualized | $2,990Computed on licensed market-return history 2006-07-31 to 2026-07-29 · proxy return 11.19% annualized | Proxy history begins 2000 — no full 30-year window |
Index-control tracking difference
Annualized fund NAV return minus the matched proxy return. Positive means the fund NAV return was higher over that window.
| Fund NAV class | 10 years | 20 years | 30 years |
|---|---|---|---|
| VIIIX | 0.09%Computed on licensed market-return history 2016-07-29 to 2026-07-29 | 0.10%Computed on licensed market-return history 2006-07-31 to 2026-07-29 | no exact shared fund NAV/proxy anchors for a full 30-year window |
| VINIX | 0.07%Computed on licensed market-return history 2016-07-29 to 2026-07-29 | 0.10%Computed on licensed market-return history 2006-07-31 to 2026-07-29 | no exact shared fund NAV/proxy anchors for a full 30-year window |
These figures are illustrations, not predictions or personalized advice. Returns and fees can differ. Read the research disclaimer.
Change the illustration
Computed from SEC filings
Assumptions for the dollar figures below: $100,000 starting amount; 5.0% annual return; 20 years; annual compounding; fees deducted annually; 0.01% computed index-control baseline. VIIIX SEC expense filing, as of 2025-12-31. Methodology.
| Result | Amount |
|---|---|
| Ending value at baseline | $264,825 |
| Ending value at filed expense ratio | $264,321 |
| Difference attributed to fee drag | $504 |
This is an illustration, not a prediction or personalized advice. Returns and fees can differ. Read the research disclaimer.
Largest active differences vs the S&P 500
The bars are labeled and repeated in the table; color is not the only signal. Linked company names open Buy Like Buffett’s company record; Sensible Investor does not score stocks.
| Holding | Fund | S&P 500 | Difference |
|---|---|---|---|
| JPMorgan Chase & Co. | 1.34% | 1.42% | -0.08% |
| Visa, Inc. | 0.88% | 0.91% | -0.03% |
| Goldman Sachs Group, Inc. (The) | 0.43% | 0.45% | -0.02% |
| Bank of America Corp. | 0.56% | 0.58% | -0.02% |
| NVIDIA Corp. | 7.60% | 7.58% | +0.01% |
| Apple, Inc. | 6.68% | 6.67% | +0.01% |
| Citigroup, Inc. | 0.34% | 0.35% | -0.01% |
| Alphabet, Inc. | 5.40% | 5.40% | +0.01% |
| Microsoft Corp. | 4.93% | 4.92% | +0.01% |
| Amazon.com, Inc. | 3.65% | 3.64% | +0.01% |
Source and verification
SEC N-PORT filing · filed 2026-05-28 · period 2026-03-31
SEC expense filing · period 2025-12-31
Cite these figures
Each snippet includes the figure’s source-event date and immutable verification URL.
Best-fit active share
Sensible Investor, “VANGUARD INSTITUTIONAL INDEX FUND — best-fit active share,” 0.2% versus the S&P 500, fund portfolio as of 2026-03-31; measured against the filed holdings of iShares Core S&P 500 ETF (IVV), as of 2026-03-31. https://sensible-investor.com/registry/viiix/as-of/363649da-fcfb-4007-87ef-de06de7710ca
VIIIX filed expense ratio
Sensible Investor, “VANGUARD INSTITUTIONAL INDEX FUND — filed expense ratio,” 0.02% for VIIIX, as of 2025-12-31. https://sensible-investor.com/registry/viiix/as-of/363649da-fcfb-4007-87ef-de06de7710ca