Data as of .
IDEF vs XDEF: which is really different?
IDEF and XDEF hold 20% of their weight in the same names.
ETFIQ Off-Index Score: XDEF scores higher
How much of it is not the index it is sold as an alternative to?
A percentile among the 379 thematic ETFs with a holdings filing. It is a position in a set, not a rating, and neither end of it is a recommendation. All thematic ETFs ranked by it · How it is computed
20% of the two portfolios are the same securities at the same weight.
What they hold in common
By the books each fund has filed, IDEF and XDEF hold 20% of their money in the same securities at the same weight.
| Holding | IDEF | XDEF |
|---|---|---|
| ROLLS-ROYCE HOLDINGS PLC | 3.29% | 8.64% |
| AIRBUS GROUP | 2.55% | 8.69% |
| BAE SYSTEMS PLC | 2.18% | 7.30% |
| THALES SA | 2.18% | 4.40% |
| LEONARDO FINMECCANICA SPA | 1.60% | 3.98% |
| SAFRAN SA | 1.30% | 8.26% |
| RHEINMETALL AG | 1.15% | 6.95% |
| KONGSBERG GRUPPEN | 0.87% | 3.92% |
| BABCOCK INTERNATIONAL GROUP PLC | 0.85% | 3.69% |
| DASSAULT AVIATION SA | 0.49% | 3.71% |
| QINETIQ GROUP PLC | 0.45% | 1.80% |
| MTU AERO ENGINES HOLDING AG | 0.41% | 4.29% |
| Only in IDEF | Only in XDEF |
|---|---|
| RTX 6.55% | DSV A/S 4.70% |
| PALANTIR TECHNOLOGIES CLASS A 5.02% | MELROSE INDUSTRIES PLC 4.28% |
| BLK CSH FND TREASURY SL AGENCY 3.77% | SAAB AB 3.87% |
| LOCKHEED MARTIN CORP 3.62% | INDRA SISTEMAS SA 3.41% |
| BOEING 3.19% | SES SA 2.22% |
| GENERAL DYNAMICS CORP 2.94% | SERCO GROUP PLC 2.09% |
| NORTHROP GRUMMAN CORP 2.58% | SENIOR PLC 0.95% |
| SPACE EXPLORATION TECHNOLOGIES COR 2.44% | EUTELSAT COMMUNICATIONS SA 0.93% |
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 May 31, 2026 and Sep 18, 2026.
Performance, window by window
| Window | Total return | vs the S&P 500 | vs the Nasdaq-100 | |||
|---|---|---|---|---|---|---|
| IDEF | XDEF | IDEF | XDEF | IDEF | XDEF | |
| 3 months | −1.6% | +1.8% | −3.9 pts | −0.5 pts | +0.9 pts | +4.3 pts |
| 6 months | −5.7% | −0.4% | −23.8 pts | −18.5 pts | −30.0 pts | −24.7 pts |
| 1 year | +4.4% | not published | −12.2 pts | not published | −17.4 pts | not published |
| Since launch | +27.2% | −99.1% | −5.6 pts | −111.5 pts | −14.2 pts | −117.1 pts |
| IDEF iShares Defense Industrials Active ETF Holds 155 stocks in defense, 36% of its weight in S&P 500 companies | XDEF Xtrackers Europe Defense Technologies ETF Holds 30 stocks in defense, 0% of its weight in S&P 500 companies | |
|---|---|---|
| Issuer | iShares | Xtrackers |
| Theme | Defense | Defense |
| In the S&P 500 | 36.2% | 0.0% |
| Active share vs the S&P 500 | 95.9% | 100.0% |
| In the Nasdaq-100 | 9.2% | 0.0% |
| Holdings | 155 | 30 |
| Top ten, share of the fund | 35.8% | 61.5% |
| Expense ratio | not published | 0.35% |
| Fee for the differing part | not published | 0.35% |
| Total return, 1 year | +4.4% | −99.1% (since launch on Jan 2, 2026) |
| vs the S&P 500 | −12.2 pts | −111.5 pts |
| vs the Nasdaq-100 | −17.4 pts | −117.1 pts |
| Below its high | −13.4% | −99.2% |
| Net assets | $4.3bn | $4m |
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 36% of the fund across 155 positions, as published by its issuer for Sep 18, 2026. Over the year to Sep 18, 2026 the fund returned +4.4% with distributions reinvested against +16.6% for the S&P 500, so a holder was behind by 12.2 pts. It sits 13.4% below its all-time high of Mar 2, 2026.
XDEF in plain words
By weight, 0% of XDEF's portfolio is stocks that are also in the S&P 500; its active share against the S&P 500 is 100%. The top ten holdings are 62% of the fund across 30 positions, as filed for May 31, 2026. Since it launched on Jan 2, 2026 the fund returned −99.1% with distributions reinvested against +12.4% for the S&P 500, so a holder was behind by 111.5 pts. It sits 99.2% below its all-time high of Jan 16, 2026.
Questions people ask
- Do IDEF and XDEF hold the same stocks?
- By their latest filings, 20% of their books are the same securities at the same weight, which is a meaningful overlap. Overlap is the sum of the smaller weight of every security they share.
- Which is more different from the S&P 500, IDEF or XDEF?
- IDEF has 36% of its weight in S&P 500 names and XDEF has 0%, so XDEF differs more from the index.
Other comparisons
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 XDEF, data as of Sep 18, 2026. https://etfiq.com/compare/themes/idef-vs-xdef Free to use with attribution; the underlying files are at Open data.