Data as of Sep 13, 2026. Both funds on the fields they both publish, from the same sources.
IDEF vs VOO: how they differ
Over the year VOO returned more, +17.6% against +4.9%.
iShares Defense Industrials Active ETF and Vanguard 500 Index Fund.
What they hold in common
By the books each fund has filed, IDEF and VOO hold 0% of their money in the same securities at the same weight.
| Only in IDEF | Only in VOO |
|---|---|
| RTX 6.72% | NVIDIA Corp 7.53% |
| PALANTIR TECHNOLOGIES CLASS A 4.71% | Apple Inc 6.61% |
| LOCKHEED MARTIN CORP 3.62% | Microsoft Corp 4.31% |
| BOEING 3.32% | Amazon.com Inc 3.63% |
| ROLLS-ROYCE HOLDINGS PLC 3.30% | Alphabet Inc 3.26% |
| GENERAL DYNAMICS CORP 2.97% | Broadcom Inc 2.78% |
| USD CASH 2.72% | Alphabet Inc 2.60% |
| THALES SA 2.61% | Micron Technology Inc 2.02% |
Weight overlap is an ETFIQ calculation: for every security both funds hold, the smaller of the two weights, summed. Above 50%, holding both is close to holding one of them twice. Holdings dated Jun 30, 2026 and Sep 10, 2026.
| IDEF iShares Defense Industrials Active ETF | VOO Vanguard 500 Index Fund | |
|---|---|---|
| Where it sits | Thematic ETF | Core index fund |
| Issuer | iShares | Vanguard |
| What it is | Defense | S&P 500 |
| Total return, 1 year | +4.9% | +17.6% |
| S&P 500 over the same days | +17.5% | +17.5% |
| Gap to the S&P 500 | −12.6 pts | +0.1 pts |
| Expense ratio | not published | 0.03% |
| Already in the S&P 500 | 36.1% | 100.0% |
| Holdings | 152 | 506 |
IDEF in plain words
By weight, 36% of IDEF's portfolio is stocks that are also in the S&P 500; its active share against the S&P 500 is 96%. The top ten holdings are 35% of the fund across 152 positions, as published by its issuer for Sep 10, 2026. Over the year to Sep 11, 2026 the fund returned +4.9% with distributions reinvested against +17.5% for the S&P 500, so a holder was behind by 12.6 pts. It sits 13.9% below its all-time high of Mar 2, 2026.
VOO in plain words
VOO is an index equity fund tracking the S&P 500. Over the year to Sep 11, 2026 it returned +17.6% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.03% a year. By its holdings filed for Jun 30, 2026, 100% of the fund by weight is stocks the S&P 500 also holds, across 506 positions, with the top ten at 36.5%.
Questions people ask
- Which returned more over the last year, IDEF or VOO?
- In the year to Sep 13, 2026, with distributions reinvested, IDEF returned +4.9% and VOO returned +17.6%, so VOO returned more. One year is one year; the longer windows are in the table.
- How much do IDEF and VOO overlap with the S&P 500?
- By their latest filed holdings, 36% of IDEF and 100% of VOO by weight is stocks the S&P 500 already holds. Between the two funds, 0% of their books are the same securities at the same weight.
- Are IDEF and VOO the same kind of fund?
- No. IDEF is a thematic ETF and VOO is an index ETF, so they are built for different jobs. The table compares what both publish: return, cost and what each actually holds.
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Where these figures came from
ETFIQ links to the documents behind every figure. It is not affiliated with any issuer, and a link is not an endorsement.
Cite this page. ETFIQ, IDEF against VOO, data as of Sep 13, 2026. https://etfiq.com/compare/any/idef-vs-voo Free to use with attribution; the underlying files are at Open data.
A comparison is not a recommendation. Standards and sources