What Sent Illumina Stock Lower

For questions about this article or underlying research, email [email protected].

Illumina (ILMN) stock fell 18.6% on Friday, October 30, 2026, while the S&P 500 lost 1.8%. The drop came the day after Illumina reported its third-quarter results on October 29 and raised its outlook for the full year. So what was in that report?

What Did Illumina Report On October 29?

Illumina beat the earnings estimate but fell short of the revenue estimate. Adjusted earnings per share were $1.44, compared with an analyst estimate of $1.36. Revenue was $1.13 billion, against an estimate of about $1.15 billion.

One item from the call provides context for those two lines. Management said the company recognized tariff refunds in the third quarter, a move that raised its operating income, margins and earnings per share but lowered its revenue. The $1.44 figure excludes those refunds, and so does the $1.17 billion of revenue management cited, which was above the estimate.

Management also raised its revenue outlook for 2026 by $30 million at the midpoint, forecasting $4.64 billion to $4.66 billion. Management said the higher outlook reflects the third quarter's outperformance and a stronger fourth quarter, with more sales of sequencing consumables on a larger base of NovaSeq X instruments. Illumina placed more than 80 of those instruments in the quarter, and earnings per share came in above the high end of management's own guidance range.

Management expects the two parts of those consumables sales to move in opposite directions in 2026, projecting mid-teens growth in clinical consumables and mid to high single-digit declines in research and applied consumables.

Did Illumina Fall Alone?

Illumina did not fall alone, though it dropped much further than its peers. Every company on its Trefis peer list fell that day, with declines ranging from 1.7% for Thermo Fisher Scientific to 8.0% for Bruker. News reports said U.S. stocks fell broadly as disappointing results from Amazon and Intel fed a selloff in artificial-intelligence stocks. Health care stocks held up, with the sector ETF, XLV, rising 0.5%.

Illumina fell more than twice as much as Bruker on a day the health care sector rose. Most of the decline belonged to the company itself, rather than its group.

Where Illumina Stock Stands After The Drop

Illumina had not recorded a drop this large in the prior 365 days. Its last move of this size was a 24.8% rise on October 31, 2025.

The stock sat far lower a year ago, posting its lowest close of the past 52 weeks at $99.01 on October 30, 2025. Measured from its close on October 29, 2025, the day before that low and just outside the 52-week window, the stock returned 148.3% through October 30, 2026, against 11.3% for the S&P 500. The drop came from near the stock's high. Illumina closed at $290.06 on October 29, just below its highest close of the past 52 weeks, $293.69 on October 5, 2026. On October 30, the stock closed at $235.99.

Illumina is expected to report its fourth-quarter results in February 2027. The figure to watch is fourth-quarter revenue, which management guided to $1.22 billion to $1.24 billion. Management said it will provide its full outlook for 2027 on that call.

What Would Another Fall In Illumina Do To Your Plan?

A fall hurts most when one stock is a large part of what you own, and selling it to spread the risk can bring a large tax bill. Our partner advisory firm offers a free strategy review of ways to put a floor under a large position and unwind it with less tax.

Request A Free Strategy Review

Spot an error or want more like this? Tell us in 10 seconds.