ETF and Mutual Fund Analysis

Holdings as of March 31, 2026

ETF and Mutual Fund Analysis

Overlap, Comparison, and Diversification for Your Portfolio

Home > Compare > VIIIX vs VOO Holdings as of March 31, 2026

VIIIX vs VOO: Portfolio Overlap

Vanguard Institutional Index Fund vs Vanguard 500 Index Fund

100.0%
Weighted portfolio overlap
Very High Overlap

The two portfolios are structurally near-identical: most of the weight sits in the same stocks, so holding both concentrates rather than spreads capital. The tier describes what the data shows, not what to do about it.

VIIIX
503 equity holdings
as of March 31, 2026
VOO
504 equity holdings
as of March 31, 2026
503 stocks held in common
Overlap View Venn Diagram
100.0% OVERLAP VIIIX VOO
Overlapping Holdings
10 Top 10 of 503 shared, by overlap contribution
# Stock VIIIX VOO Overlap%
1
NVDA
 7.60% 7.59% 7.59%
2
AAPL
 6.68% 6.68% 6.68%
3
MSFT
 4.93% 4.93% 4.93%
4
AMZN
 3.65% 3.65% 3.65%
5
GOOGL
 3.00% 3.00% 3.00%
6
AVGO
 2.63% 2.63% 2.63%
7
GOOG
 2.40% 2.40% 2.40%
8
META
 2.24% 2.24% 2.24%
9
TSLA
 1.87% 1.87% 1.87%
10
BRK.B
 1.57% 1.57% 1.57%
Most Divergent Holdings Stocks held by one fund but absent from the other
Only in VOO — VANGUARD 500 INDEX FUND
StockWeight
ABIOMED Inc0.00%

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Frequently Asked Questions (FAQs)
What is the portfolio overlap between VIIIX and VOO?

VIIIX (Vanguard Institutional Index Fund) and VOO (Vanguard 500 Index Fund) share 100.0% portfolio overlap as of their March 31, 2026 filings, across 503 common stocks. Overlap is the sum of the smaller weight of each shared stock, so it reads as the share of a dollar that lands on the same companies in both funds.

Do VIIIX and VOO invest in the same stocks?

Almost entirely. These funds hold nearly identical portfolios and offer little differentiation between them.

What are the top stocks held by both VIIIX and VOO?

The most prominent shared holdings (by combined weight) are: NVDA, AAPL, MSFT. See the full common-holdings table on this page for weights in each fund.

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