Biogen Inc. (BIIB) was officially removed from the Nasdaq‑100 index effective prior to market open on December 22, 2025, following the index’s annual reconstitution announced on December 15, 2025. The reconstitution added six new companies—Alnylam Pharmaceuticals, Ferrovial SE, Insmed Incorporated, Monolithic Power Systems, Seagate Technology Holdings, and Western Digital Corp.—and dropped six, including Biogen, CDW, GlobalFoundries, Lululemon, ON Semiconductor, and The Trade Desk.
The removal was driven by Biogen’s market capitalization of $25.55 billion and its average daily trading volume of roughly 180,000 shares, both below the Nasdaq‑100’s inclusion thresholds of $30 billion and 200,000 shares, respectively. In addition, the company’s sector mix no longer aligned with the index’s emphasis on technology and growth sectors, further contributing to its exclusion.
Index‑tracking funds such as the Invesco QQQ Trust, which must hold every constituent of the Nasdaq‑100, will sell Biogen shares to comply with the new composition. The resulting reduction in passive demand is expected to lower trading volume and could modestly increase the company’s cost of capital by reducing liquidity and visibility in the market.
The removal signals that Biogen’s relative performance has lagged behind its peers, reflecting a decline in market cap growth and a shift in investor focus toward higher‑growth technology names. While the company remains listed on Nasdaq, the loss of index status may influence institutional allocation decisions and alter the perception of its stability and growth prospects.
Biogen’s management has not announced any immediate strategic changes in response to the index shift, but the company will likely monitor passive fund flows and consider initiatives to improve liquidity and market cap to regain inclusion in future reconstitutions. Investors should watch for potential adjustments in capital structure or strategic partnerships that could enhance the company’s index eligibility and market visibility.
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