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Illumina ILMN stock price chart showing 2026 rally ahead of S&P 500 re-entry
Photo: TipRanks

Illumina Stock Jumps 12% on S&P 500 Return

S&P Dow Jones Indices2 min read6 sources

Why is Illumina stock up today?

Illumina (ILMN) stock rose 12.4% to $245.18 since its Friday, September 4 S&P 500 readmission announcement, pushed higher by index funds buying ahead of the Monday, September 21 effective date.

Key numbers

ILMN price (Sept 17 close)$245.18+12.4% since Sept 4 announcement
ILMN YTD gain 2026+87%from ~$131 at Jan 1, 2026 open to $245.18
ILMN market cap$37.0Bas of Sept 17, 2026
ILMN Q2 2026 revenue$1.16B+9.5% YoY, beat est. $1.13B
ILMN FY2026 revenue guidance$4.60–$4.64Braised ~11% at midpoint vs. prior
TTD price (Sept 17)$14.49–74% from 52-wk high of $56.39

What happened

Illumina (ILMN) stock rose 12.4% to $245.18 since its Friday, September 4 S&P 500 readmission announcement, pushed higher by index funds buying ahead of the Monday, September 21 effective date. S&P Dow Jones Indices said Illumina, Everpure (P), and Bloom Energy (BE) are joining, replacing The Trade Desk (TTD), Builders FirstSource (BLDR), and Molson Coors (TAP). Illumina was removed from the S&P 500 in June 2024 when it spun off cancer-test maker GRAIL and dropped into the smaller MidCap 400. The comeback follows a Q2 revenue beat — sales up 9.5% to $1.16 billion compared with a year ago — and Buy upgrades from UBS, which set a $260 target, and Argus, which raised its target to $235.

Why it matters

Illumina's return to the S&P 500 means every index fund and ETF tracking the benchmark — managing trillions of dollars — must now buy ILMN shares, creating near-guaranteed institutional demand. That wave of buying, concentrated in the days before the September 21 effective date, is what has pushed the stock up sharply since the announcement. Longer term, index membership brings visibility to a company that makes the DNA-reading machines behind cancer detection and genetic disease testing, a market growing fast as genomic tools move from research labs into everyday medicine.

Who this affects

Marketbullish
Medium impact
Index funds must buy ILMN; removed stocks lose support.
Companybullish
High impact
Illumina gains broader institutional ownership and analyst attention.
Competitorsneutral
Low impact
Genomics peers unaffected; TTD, BLDR lose index fund support.
Industrybullish
Low impact
Genomics tools gain S&P 500 visibility as DNA testing grows.

Illumina vs Thermo Fisher, 10x Genomics, Pacific Biosciences

IlluminaILMN:NASDAQ$37.0B+87%43x+9.5%
Thermo FisherTMO:NYSE$218B—~22x+4%
10x GenomicsTXG:NASDAQ$10.3B——+3%
Pacific BiosciencesPACB:NASDAQ$0.2B———

As of 2026-09-17

How we got here

  1. Illumina dropped from S&P 500 after GRAIL spinoff; moves to MidCap 400.

  2. ILMN jumps after Q2 2026 earnings beat; sales up 9.5% YoY to $1.16B.

  3. S&P announces ILMN, Everpure, Bloom Energy join S&P 500; TTD, BLDR, TAP exit.

  4. UBS upgrades ILMN to Buy with $260 target; Argus raises target to $235.

  5. ILMN, Everpure (P), Bloom Energy (BE) join S&P 500 at Monday market open.

What to watch

  • Whether ILMN holds gains after index rebalancing completes Sept 21.2026-09-22
  • Trade Desk (TTD) Q3 earnings after layoffs and index removal pressure shares.Q4 2026
  • ILMN Q3 2026 revenue vs. raised full-year guidance of $4.60–$4.64B.Q4 2026

Educational content only. Not investment advice.

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