Affymetrix, Inc. (AFFX)

Affymetrix developed tools for genetic analysis, best known for its GeneChip microarrays. These small glass chips held hundreds of thousands of DNA probes and let scientists measure gene activity or detect genetic variation across an entire genome in a single experiment. Its products were used by academic researchers, drug companies and, increasingly, clinical labs.

The company was founded in the early 1990s in Silicon Valley, building on research that adapted semiconductor photolithography to make DNA arrays. It went public on NASDAQ in 1996 under the symbol AFFX and was based in Santa Clara, California. In the late 1990s and 2000s its microarrays became a standard research tool and helped drive large genome-wide association studies.

From around 2008 Affymetrix faced growing pressure as next-generation DNA sequencing from Illumina and others took over much of the genomics research market. Revenue stalled and the company went through restructurings. It diversified by buying eBioscience in 2012, adding antibodies and cell analysis reagents, and it pushed into clinical and agricultural genotyping applications.

In January 2016 Thermo Fisher Scientific agreed to buy Affymetrix for $14.00 per share in cash, about $1.3 billion. After stockholders approved the deal at a special meeting, the acquisition closed on March 31, 2016 and the shares were removed from NASDAQ. Affymetrix's products continue to be sold within Thermo Fisher's life sciences business.