Biogen Shares Surge 4.37% on $250M Trading Frenzy Ranks 443rd in Volume

. 11, 2025, . The biotech giant's rally followed a regulatory filing disclosing a potential partnership with a European firm to co-develop a novel Alzheimer’s therapeutic candidate, which analysts noted could expand its late-stage pipeline diversity. Market participants also highlighted renewed investor confidence in management’s guidance for 2026 R&D expenditures, signaling stability in its core neurology and rare disease programs.

Short-term momentum was further supported by a Bloomberg-verified update on its Tysabri biosimilar litigation, where a federal court dismissed a key claim from a competitor, reducing near-term legal headwinds. While the ruling does not preclude future appeals, it removed immediate uncertainty around market share retention in the multiple sclerosis segment. Analysts at a major Wall Street firm downgraded the stock to "market outperform" from "equal weight," citing improved risk-reward dynamics post-legal developments.

I’m happy to help set up this back-test, but a couple of practical details need to be clarified before we can proceed: 1. Universe • Which market should we screen for the “top 500 stocks by daily trading volume”? (e.g., all U.S. listed equities, a specific exchange, or a global universe) 2. Execution assumptions • Do you want to buy at today’s close and sell at the next day’s close? (That’s the standard interpretation of “hold for 1 day.”) • If you’d prefer a different convention—such as buy at tomorrow’s open—let me know. 3. Data & implementation constraints • A full daily rebalance across 500 tickers requires multi-asset portfolio back-testing, which is more advanced than the single-ticker engine that’s directly available here. • Two common work-arounds are: a) Use an index or ETF that already tracks the highest-volume names (e.g., a liquidity-weighted ETF) as a proxy. b) Narrow the scope (e.g., top 50 names) and back-test them individually or in batches. Please let me know your preferences (especially the market universe and acceptable proxy or scope adjustment). Once we’ve nailed these down, I’ll generate the data-retrieval plan and run the back-test.