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IDEF vs XBI: which is really different?

IDEF and XBI hold 0% of their weight in the same names, and XBI returned +45.0% over the year. iShares Defense Industrials and Tech Active ETF and State Street(R) SPDR(R) S&P(R) Biotech ETF.

XBI costs 0.20 points a year less; their one-year returns differ by 48.3 points; XBI is 2.6 times larger.

IDEFXBI
Expense ratio0.55%0.35%
Net assets, IDEF as of Oct 9, 2026 and XBI as of Oct 8, 2026$3.8bn$9.9bn
Total return, 1 year−3.3%+45.0%
What it tracksDefenseBiotech
Holdings in common0%
S&P 500, total return, 1 year+17.3%
Against the S&P 500, 1 yearbehind by 20.6 ptsahead by 27.7 pts
Below its all-time high15.1%, high on Mar 2, 202611.1%, high on Feb 8, 2021

Holdings in common uses holdings dated Oct 8, 2026.

41.2%
IDEF in the S&P 500
12.7%
XBI in the S&P 500
−3.3%
IDEF total return, 1 year
+45.0%
XBI total return, 1 year
IDEF · 1 year to Oct 9, 202659% of its weight is outside the S&P 500
59% of its weight is outside the S&P 50041% of IDEF's weight is in S&P 500 companies and 59% is outside the index. Holdings as of Oct 8, 2026.41%59%of its weight in S&P 500 companiesof its weight outside the S&P 500active share 90% · top ten 31% of the fund · 155 holdings as published by its issuer for Oct 8, 2026 · Nasdaq-100: 16% in59% of its weight is outside the S&P 50041% of IDEF's weight is in S&P 500 companies and 59% is outside the index. Holdings as of Oct 8, 2026.41%59%in the S&P 500outside the S&P 500active share 90% · Nasdaq-100: 16% in

41% of IDEF's weight is in S&P 500 companies and 59% is outside the index. Holdings as of Oct 8, 2026.

XBI · 1 year to Oct 9, 202687% of its weight is outside the S&P 500
87% of its weight is outside the S&P 50013% of XBI's weight is in S&P 500 companies and 87% is outside the index. Holdings as of Oct 8, 2026.13%87%inof its weight outside the S&P 500active share 98% · top ten 17% of the fund · 165 holdings as published by its issuer for Oct 8, 2026 · Nasdaq-100: 9% in87% of its weight is outside the S&P 50013% of XBI's weight is in S&P 500 companies and 87% is outside the index. Holdings as of Oct 8, 2026.13%87%inof its weight outside the S&P 500active share 98% · Nasdaq-100: 9% in

13% of XBI's weight is in S&P 500 companies and 87% is outside the index. Holdings as of Oct 8, 2026.

ETFIQ Off-Index Score · XBI scores higherHow much of it is not the index it is sold as an alternative to?
0.1, the lowest in this set92.3, the highest

A percentile among the 391 thematic ETFs with a holdings filing. All thematic ETFs ranked by it → How it is computed →

What they hold in common

By the books each fund has filed, IDEF and XBI hold 0% of their money in the same securities at the same weight. Above 50%, holding both is close to holding one of them twice. Holdings dated Oct 8, 2026.

half

0% in common

Positions both hold, largest shared weight first
Holding IDEF XBI
Only in IDEF
RTX 5.07%
PALANTIR TECHNOLOGIES CLASS A 4.36%
LOCKHEED MARTIN CORP 3.32%
SPACE EXPLORATION TECHNOLOGIES COR 3.13%
ROLLS-ROYCE HOLDINGS PLC 2.91%
GENERAL DYNAMICS CORP 2.90%
BOEING 2.82%
NORTHROP GRUMMAN CORP 2.64%
Only in XBI
MODERNA INC 2.20%
TWIST BIOSCIENCE CORP 1.84%
NATERA INC 1.79%
ABBVIE INC 1.65%
UNITED THERAPEUTICS CORP 1.59%
AMGEN INC 1.58%
BIOGEN INC 1.57%
HALOZYME THERAPEUTICS INC 1.55%

0% of the two portfolios are the same securities at the same weight.

Performance, window by window

Total returnvs the S&P 500vs the Nasdaq-100
WindowIDEFXBIIDEFXBIIDEFXBI
3 months−2.5%−3.3%−5.8 pts−6.7 pts−6.1 pts−7.0 pts
6 months−8.5%+18.9%−23.6 pts+3.8 pts−31.7 pts−4.3 pts
1 year−3.3%+45.0%−20.6 pts+27.7 pts−26.9 pts+21.4 pts
3 yearsnot published+114.6%not published+28.8 ptsnot published+7.3 pts
Since launch
IDEF May 2025 · XBI Feb 2006
+24.7%+890.7%−11.1 pts+92.2 pts−22.7 pts−1,164.7 pts

Source: ETFIQ. Open the live comparison on ETFIQ →

On the same fields

IDEF
iShares Defense Industrials and Tech Active ETF · Holds 155 stocks in defense, 41% of its weight in S&P 500 companies
XBI
State Street(R) SPDR(R) S&P(R) Biotech ETF · Holds 165 stocks in biotech, 13% of its weight in S&P 500 companies
Issuer iShares State Street
Theme Defense Biotech
In the S&P 500 41.2% 12.7%
Active share vs the S&P 500 89.8% 98.4%
In the Nasdaq-100 15.8% 8.5%
Holdings 155 165
Top ten, share of the fund 31.2% 16.9%
Expense ratio 0.55% 0.35%
Fee for the differing part 0.61% 0.36%
Total return, 1 year −3.3% +45.0%
vs the S&P 500 −20.6 pts +27.7 pts
vs the Nasdaq-100 −26.9 pts +21.4 pts
Below its high −15.1% −11.1%
Net assets, IDEF as of Oct 9, 2026 and XBI as of Oct 8, 2026 $3.8bn $9.9bn

As of Oct 9, 2026. Source: ETFIQ.

IDEF in plain words

By weight, 41% of IDEF's portfolio is stocks that are also in the S&P 500; its active share against the S&P 500 is 90%. The top ten holdings are 31% of the fund across 155 positions, as published by its issuer for Oct 8, 2026. Over the year to Oct 9, 2026 the fund returned −3.3% with distributions reinvested against +17.3% for the S&P 500, so a holder was behind by 20.6 pts. It sits 15.1% below its all-time high of Mar 2, 2026.

XBI in plain words

By weight, 13% of XBI's portfolio is stocks that are also in the S&P 500; its active share against the S&P 500 is 98%. The top ten holdings are 17% of the fund across 165 positions, as published by its issuer for Oct 8, 2026. Over the year to Oct 9, 2026 the fund returned +45.0% with distributions reinvested against +17.3% for the S&P 500, so a holder was ahead by 27.7 pts. It sits 11.1% below its all-time high of Feb 8, 2021.

Questions people ask

Do IDEF and XBI hold the same stocks?
By their latest filings, 0% of their books are the same securities at the same weight, which is mostly different names. Overlap is the sum of the smaller weight of every security they share.
Which is more different from the S&P 500, IDEF or XBI?
IDEF has 41% of its weight in S&P 500 names and XBI has 13%, so XBI differs more from the index.
Which is cheaper, IDEF or XBI?
IDEF charges 0.55% a year and XBI charges 0.35%, so XBI is cheaper. Fees come from each fund's prospectus.
Other comparisons
IDEF vs IBBIDEF vs AIQIDEF vs AIRRIDEF vs GDXJXBI vs XARXBI vs SHLDXBI vs PPAXBI vs ITA
IDEF on its own →XBI on its own →How every figure is computed →Standards and sources →
Where these figures came from
IDEF filings on SEC EDGAR ↗IDEF prospectus with the expense ratio (SEC) ↗iShares page for IDEF ↗XBI filings on SEC EDGAR ↗XBI prospectus with the expense ratio (SEC) ↗State Street website ↗

ETFIQ links to the documents behind every figure; a link is not an endorsement. A comparison is not a recommendation.

How this is computed

It is a position in a set, not a rating, and neither end of it is a recommendation.

Weight overlap is an ETFIQ calculation: for every security both funds hold, the smaller of the two weights, summed.

Every figure is an ETFIQ calculation with distributions reinvested.

Cite this page

ETFIQ, IDEF against XBI, data as of Oct 9, 2026. https://etfiq.com/compare/themes/idef-vs-xbi

Open data

Free to use with attribution for figures ETFIQ computes; issuer data stays under its owner's terms.