XBI · WMTMT

Sep 30Oct 2Oct 6Oct 7Oct 9

Breadth

107 / 157

stocks fell with the index

Concentration

29%

of the decline from TWST, NKTR, INSM

Biggest driver

TWST −0.58

TWIST BIOSCIENCE CORP, −17.32%

Biggest offset

MRNA +0.53

MODERNA INC, +16.84%

What drove it

157 members · detractors first · QTD · residual 16.3bp within 60bp gate

The XBI fell 2.49% (−3.93 pts) so far this quarter on a mixed tape; TWST, NKTR, INSM did most of the damage, with 29% of the decline between them.

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

+2.7 pts from 45 gainers−6.6 pts from 112 losers

net −3.9 pts · losers outweigh gainers 2.5 to 1

Stock

Points

Return

XBIsum of all 157 stocks

−3.9

−2.49%

TWSTTWIST BIOSCIENCE CORP

−0.6

−17.32%

NKTRNEKTAR THERAPEUTICS

−0.3

−32.00%

INSMINSMED INC

−0.3

−11.86%

PRAXPRAXIS PRECISION MEDICINES I

−0.2

−10.77%

TVTXTRAVERE THERAPEUTICS INC

−0.2

−11.47%

VKTXVIKING THERAPEUTICS INC

−0.2

−12.55%

CELCCELCUITY INC

−0.2

−14.56%

AVBPARRIVENT BIOPHARMA INC

−0.2

−44.75%

SRRKSCHOLAR ROCK HOLDING CORP

−0.2

−12.69%

RVMDREVOLUTION MEDICINES INC

−0.2

−7.55%

BMRNBIOMARIN PHARMACEUTICAL INC

−0.2

−8.67%

CGONCG ONCOLOGY INC

−0.2

−9.97%

INCYINCYTE CORP

−0.1

−7.05%

MDGLMADRIGAL PHARMACEUTICALS INC

−0.1

−6.39%

DNTHDIANTHUS THERAPEUTICS INC

−0.1

−6.45%

127 othersclick to expand the full index

−2.8

PRMEPRIME MEDICINE INC

+0.1

+30.61%

GILDGILEAD SCIENCES INC

+0.1

+1.42%

DYNDYNE THERAPEUTICS INC

+0.1

+3.29%

EXELEXELIXIS INC

+0.1

+2.48%

NTLAINTELLIA THERAPEUTICS INC

+0.1

+8.37%

RXRXRECURSION PHARMACEUTICALS A

+0.1

+5.57%

BEAMBEAM THERAPEUTICS INC

+0.1

+5.11%

UTHRUNITED THERAPEUTICS CORP

+0.1

+1.34%

KODKODIAK SCIENCES INC

+0.1

+5.35%

ABBVABBVIE INC

+0.1

+5.68%

IBRXIMMUNITYBIO INC

+0.1

+11.33%

NVAXNOVAVAX INC

+0.1

+17.95%

ERASERASCA INC

+0.2

+9.35%

PCVXVAXCYTE INC

+0.5

+25.45%

MRNAMODERNA INC

+0.5

+16.84%

Cap weighting, illustrated

TWIST BIOSCIENCE CORP and BRIDGEBIO ONCOLOGY THERAPEUT moved almost identically (−17.32% vs −19.27%), yet TWST moved the XBI 58.4× 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 −3.93 pt move · cell size = points contributed · color = direction, intensity = return

TWST−0.6 pts(−17.3%)

MRNA+0.5 pts(+16.8%)

PCVX+0.5 pts(+25.4%)

NKTR−0.3 pts(−32.0%)

INSM−0.3 pts(−11.9%)

PRAX−0.2 pts(−10.8%)

TVTX−0.2 pts(−11.5%)

VKTX−0.2 pts(−12.5%)

CELC−0.2 pts

AVBP−0.2 pts

SRRK−0.2 pts(−12.7%)

RVMD−0.2 pts(−7.6%)

BMRN−0.2 pts(−8.7%)

ERAS+0.2 pts

CGON−0.2 pts

INCY

MDGL−0.1 pts(−6.4%)

NVAX+0.1 pts

IBRX+0.1 pts

ABBV+0.1 pts

DNTH

KOD

IMVT−0.1 pts

SYRE−0.1 pts

CYTK−0.1 pts

ALNY

NTRA

PGEN−0.1 pts

RYTM−0.1 pts

UTHR

ARWR

CRSP

BHVN

RXRX

NTLA

SLS

VERA

37 more

ROIV

EXEL

IDYA

ORIC

GILD

CAPR

COGT

GLUE

PTGX

ABSI

TNGX

ANAB

IRON

AVTX

VCYT

MLYS

IONS

REGN

TYRA

Concentration curve

cumulative share of the −3.93 pt move · sorted by contribution

When they drove it

cumulative points through the period

Breadth

member returns, this period

−50%−30%−10%+10%+30%

From −44.75% (AVBP) to +30.61% (PRME). Equal-weight, the XBI would be −3.14% vs the actual −2.49%; the gap is what cap weighting did.

By sector

point contribution · sums to −3.93 pts

-157

−3.9

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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