XBI · WMTMT

Sep 10Sep 17Sep 25Oct 2Oct 9

Breadth

113 / 157

stocks fell with the index

Concentration

74%

of the decline from QURE, PRAX, ARWR

Biggest driver

QURE −1.11

UNIQURE NV, −49.20%

Biggest offset

MRNA +1.72

MODERNA INC, +64.69%

What drove it

157 members · detractors first · 1M · residual 127.8bp exceeds 60bp gate

The XBI fell 1.96% (−3.07 pts) on the month, and 74% of that decline came from just three stocks: QURE, PRAX, ARWR.

Read the latest market-close note: Goldman and Microsoft Push the Dow to a Large Gain While Telecoms Sink Communication Services

+13.0 pts from 47 gainers−16.3 pts from 110 losers

net −3.1 pts · losers outweigh gainers 1.2 to 1

Stock

Points

Return

XBIsum of all 157 stocks

−3.1

−1.96%

QUREUNIQURE NV

−1.1

−49.20%

PRAXPRAXIS PRECISION MEDICINES I

−0.6

−23.25%

ARWRARROWHEAD PHARMACEUTICALS IN

−0.6

−24.18%

VKTXVIKING THERAPEUTICS INC

−0.6

−11.27%

DNTHDIANTHUS THERAPEUTICS INC

−0.5

−20.25%

ACADACADIA PHARMACEUTICALS INC

−0.5

−28.70%

TVTXTRAVERE THERAPEUTICS INC

−0.5

−22.79%

SRRKSCHOLAR ROCK HOLDING CORP

−0.5

−24.21%

INSMINSMED INC

−0.4

−20.96%

NKTRNEKTAR THERAPEUTICS

−0.4

−41.73%

IONSIONIS PHARMACEUTICALS INC

−0.4

−18.63%

BMRNBIOMARIN PHARMACEUTICAL INC

−0.4

−16.36%

ORKAORUKA THERAPEUTICS INC

−0.4

−10.41%

ROIVROIVANT SCIENCES LTD

−0.4

−13.43%

CYTKCYTOKINETICS INC

−0.4

−14.55%

127 othersclick to expand the full index

−6.5

ABBVABBVIE INC

+0.2

+8.41%

ABSIABSCI CORP

+0.2

+23.30%

AMGNAMGEN INC

+0.2

+8.47%

NVAXNOVAVAX INC

+0.2

+37.10%

RXRXRECURSION PHARMACEUTICALS A

+0.4

+37.97%

VCYTVERACYTE INC

+0.4

+7.61%

PCVXVAXCYTE INC

+0.4

+21.19%

IBRXIMMUNITYBIO INC

+0.5

+36.14%

CDNACAREDX INC

+0.5

+27.29%

NTRANATERA INC

+0.7

+22.86%

GRALGRAIL INC

+1.3

+81.25%

TWSTTWIST BIOSCIENCE CORP

+1.3

+25.96%

KODKODIAK SCIENCES INC

+1.3

+203.83%

IOVAIOVANCE BIOTHERAPEUTICS INC

+1.4

+79.61%

MRNAMODERNA INC

+1.7

+64.69%

Cap weighting, illustrated

PRAXIS PRECISION MEDICINES I and CRESCENT BIOPHARMA INC moved almost identically (−23.25% vs −23.38%), yet PRAX moved the XBI 25.9× as much. In a cap-weighted index, the bigger company's weight turns the same percentage move into far more points.

Attribution map

slicing the −3.07 pt move · cell size = points contributed · color = direction, intensity = return

MRNA+1.7 pts(+64.7%)

IOVA+1.4 pts(+79.6%)

KOD+1.3 pts(+203.8%)

TWST+1.3 pts(+26.0%)

GRAL+1.3 pts(+81.3%)

QURE−1.1 pts

NTRA+0.7 pts(+22.9%)

PRAX−0.6 pts(−23.2%)

ARWR−0.6 pts

VKTX−0.6 pts

DNTH−0.5 pts

ACAD−0.5 pts

TVTX−0.5 pts

SRRK−0.5 pts

CDNA

IBRX+0.5 pts(+36.1%)

INSM−0.4 pts(−21.0%)

PCVX+0.4 pts

VCYT+0.4 pts

RXRX

NKTR

IONS−0.4 pts

BMRN−0.4 pts

ORKA

ROIV−0.4 pts

CYTK−0.4 pts

ALKS

CGON

CELC

IMVT−0.3 pts

NVAX

IMNM

MIRM

NBIX

AMGN

ABSI

BBIO

VRDN

EXEL

INCY

CLDX

PTCT

SYRE

MLYS

ARQT

ERAS

GLUE

REGN

UTHR

IRON

PGEN

JBIO

BEAM

BIIB

IMMX

AGIO

TRAX

Concentration curve

cumulative share of the −3.07 pt move · sorted by contribution

When they drove it

cumulative points through the period

Breadth

member returns, this period

−100%0%+100%+200%

From −51.56% (CMPX) to +203.83% (KOD). Equal-weight, the XBI would be −6.28% vs the actual −1.96%; the gap is what cap weighting did.

By sector

point contribution · sums to −3.07 pts

-157

−3.2

The year, session by session

every trading day of 2026 · hover for the move

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SPDR S&P Biotech ETF

What drove it

Attribution map

Concentration curve

When they drove it

Breadth

By sector

The year, session by session

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