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IBB vs IDEF: which is really different?

IBB and IDEF hold 0% of their weight in the same names, and IBB returned +36.1% over the year. iShares Biotechnology ETF and iShares Defense Industrials and Tech Active ETF.

IBB costs 0.11 points a year less; their one-year returns differ by 39.4 points; IBB is 2.8 times larger.

IBBIDEF
Expense ratio0.44%0.55%
Net assets, as of Oct 8, 2026$10.3bn$3.7bn
Total return, 1 year+36.1%−3.3%
What it tracksBiotechDefense
Holdings in common0%
S&P 500, total return, 1 year+17.3%
Against the S&P 500, 1 yearahead by 18.8 ptsbehind by 20.6 pts
Below its all-time high15.1%, high on Mar 2, 2026

Holdings in common uses holdings dated Oct 8, 2026.

39.5%
IBB in the S&P 500
41.2%
IDEF in the S&P 500
+36.1%
IBB total return, 1 year
−3.3%
IDEF total return, 1 year
IBB · 1 year to Oct 9, 202661% of its weight is outside the S&P 500
61% of its weight is outside the S&P 50040% of IBB's weight is in S&P 500 companies and 61% is outside the index. Holdings as of Oct 8, 2026.40%61%of its weight in S&P 500 companiesof its weight outside the S&P 500active share 99% · top ten 50% of the fund · 245 holdings as published by its issuer for Oct 8, 2026 · Nasdaq-100: 33% in61% of its weight is outside the S&P 50040% of IBB's weight is in S&P 500 companies and 61% is outside the index. Holdings as of Oct 8, 2026.40%61%in the S&P 500outside the S&P 500active share 99% · Nasdaq-100: 33% in

40% of IBB's weight is in S&P 500 companies and 61% is outside the index. Holdings as of Oct 8, 2026.

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.

ETFIQ Off-Index Score · IBB 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, IBB and IDEF 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 IBB IDEF
Only in IBB
GILEAD SCIENCES 8.37%
AMGEN INC 7.89%
VERTEX PHARMACEUTICALS 7.69%
REGENERON PHARMACEUTICALS 5.40%
MODERNA 5.30%
NATERA 3.88%
ARGENX SE ADR 3.35%
ILLUMINA INC 2.94%
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%

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
WindowIBBIDEFIBBIDEFIBBIDEF
3 months+7.5%−2.5%+4.1 pts−5.8 pts+3.9 pts−6.1 pts
6 months+21.9%−8.5%+6.8 pts−23.6 pts−1.3 pts−31.7 pts
1 year+36.1%−3.3%+18.8 pts−20.6 pts+12.5 pts−26.9 pts
3 years+69.1%not published−16.7 ptsnot published−38.2 ptsnot published
Since launch
IBB Feb 2001 · IDEF May 2025
+525.3%+24.7%−299.7 pts−11.1 pts−936.3 pts−22.7 pts

Source: ETFIQ. Open the live comparison on ETFIQ →

On the same fields

IBB
iShares Biotechnology ETF · Holds 245 stocks in biotech, 40% of its weight in S&P 500 companies
IDEF
iShares Defense Industrials and Tech Active ETF · Holds 155 stocks in defense, 41% of its weight in S&P 500 companies
Issuer iShares iShares
Theme Biotech Defense
In the S&P 500 39.5% 41.2%
Active share vs the S&P 500 99.0% 89.8%
In the Nasdaq-100 33.1% 15.8%
Holdings 245 155
Top ten, share of the fund 49.9% 31.2%
Expense ratio 0.44% 0.55%
Fee for the differing part 0.44% 0.61%
Total return, 1 year +36.1% −3.3%
vs the S&P 500 +18.8 pts −20.6 pts
vs the Nasdaq-100 +12.5 pts −26.9 pts
Below its high −4.8% −15.1%
Net assets, as of Oct 8, 2026 $10.3bn $3.7bn

As of Oct 9, 2026. Source: ETFIQ.

IBB in plain words

By weight, 40% of IBB's portfolio is stocks that are also in the S&P 500; its active share against the S&P 500 is 99%. The top ten holdings are 50% of the fund across 245 positions, as published by its issuer for Oct 8, 2026. Over the year to Oct 9, 2026 the fund returned +36.1% with distributions reinvested against +17.3% for the S&P 500, so a holder was ahead by 18.8 pts.

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.

Questions people ask

Do IBB and IDEF 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, IBB or IDEF?
IBB has 40% of its weight in S&P 500 names and IDEF has 41%, so IBB differs more from the index.
Which is cheaper, IBB or IDEF?
IBB charges 0.44% a year and IDEF charges 0.55%, so IBB is cheaper. Fees come from each fund's prospectus.
Other comparisons
IBB vs SHLDIBB vs PPAIBB vs XARIBB vs ITAIDEF vs XBIIDEF vs AIRRIDEF vs GRIDIDEF vs PPA
IBB on its own →IDEF on its own →How every figure is computed →Standards and sources →
Where these figures came from
IBB filings on SEC EDGAR ↗IBB prospectus with the expense ratio (SEC) ↗iShares page for IBB ↗IDEF filings on SEC EDGAR ↗iShares page for IDEF ↗

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

Open data

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