BIIB.SW falls 36% to CHF147.46 on SIX close 02 Mar 2026: analysts eye rerating

BIIB.SW stock dropped 36.44% to CHF147.46 on the SIX close on 02 Mar 2026, marking one of the largest single-session declines for Biogen Inc. The fall followed a sharp gap from the previous close of CHF232.00, with reported volume at 2.00 shares versus an average of 23,502.00. Investors reacted to mixed clinical updates and valuation re-rates in the Healthcare sector, pushing Biogen’s market cap to about CHF19.09B on the Switzerland exchange.