iShares Biotechnology ETF (IBB)

Look-through valuation · Theme · Expense ratio 0.45 % · ISIN US4642875565

IBB iShares Biotechnology ETF IBB overvalued

Holdings vs fair value −46.9 % weighted average

Quality 59/100 avg alpha quality

Expense ratio 0.45 % per year (TER)

Fund size $ 7.8B yield 0.22 %

The look-through covers 97 % of the fund by weight (217 of 240 disclosed positions valued). Unresolved positions are left out, never estimated.

Price history (since 2001)

Monthly close since 2001. Price shows performance, the valuation verdict is in the look-through above.

Top holdings

Holding	Weight	vs fair value	Quality
Vertex Pharmaceuticals Inc VRTX	7.8 %	−42.6 %	73
Amgen Inc AMGN	7.7 %	−29.7 %	67
Gilead Sciences Inc GILD	7.1 %	+11.2 %	77
Regeneron Pharmaceuticals Inc REGN	5.2 %	−10.5 %	66
argenx NV ADR ARGX	3.5 %	−60.2 %	75
Alnylam Pharmaceuticals Inc ALNY	2.9 %	−78.6 %	56
Natera Inc NTRA	2.9 %	−80.0 %	46
Revolution Medicines Inc RVMD	2.8 %	−80.0 %	38
Illumina Inc ILMN	2.3 %	−49.0 %	82
Biogen Inc BIIB	2.2 %	−3.9 %	70
Moderna Inc MRNA	1.9 %	−80.0 %	52
BeiGene, Ltd. ONC	1.9 %	−63.3 %	66
Insmed Inc INSM	1.9 %	−83.0 %	31
Incyte Corporation INCY	1.8 %	+0.6 %	88
United Therapeutics Corporation UTHR	1.7 %	+21.2 %	73
Roivant Sciences Ltd ROIV	1.4 %	−80.0 %	49
Neurocrine Biosciences Inc NBIX	1.3 %	−45.7 %	75
Ascendis Pharma AS ASND	1.3 %	−80.0 %	67
Genmab AS GMAB	1.2 %	n/a	n/a
BridgeBio Pharma Inc BBIO	1.1 %	−79.7 %	39
Exelixis Inc EXEL	1.1 %	−7.4 %	88
Medpace Holdings Inc MEDP	1.0 %	−46.7 %	77
Madrigal Pharmaceuticals Inc MDGL	0.9 %	−78.6 %	48
Biomarin Pharmaceutical Inc BMRN	0.9 %	−32.6 %	63
Bio-Techne Corp TECH	0.9 %	−80.0 %	65

Fair value and quality per position come from the same valuation as our stock pages. Showing the 25 largest of 240 disclosed positions. "n/a" means the position is not (yet) in our stock universe and does not enter the average.

How the look-through works

An ETF has no fair value of its own like a single stock. We build it bottom up: every holding has a fair value and a quality score on our pages. Weighted by portfolio share, that gives iShares Biotechnology ETF an average of how cheap or expensive its companies currently sit versus fair value, and how high their average quality is.

As of: Jul 17, 2026

No investment advice, no buy or sell recommendation. The look-through is a computed summary of public fundamentals and is no substitute for your own research.