Biogen Inc. (BIIB)
BIIB moved a median of -0.01% 30 minutes after news, and +0.15% by the close. How BIIB actually reacts to news — the realized, point-in-time move the market made, measured across 1,208 labeled events over the last three years with zero look-ahead.
BIIB’s median reaction, across the day.
| Horizon | Median | % positive | Events |
|---|---|---|---|
| 5-min | +0.03% | 53% | 1,203 |
| 30-min | -0.01% | 49% | 1,203 |
| 60-min | +0.03% | 51% | 1,203 |
| to close | +0.15% | 54% | 1,206 |
| Middle 50% of BIIB reactions | -0.58% to +0.61% |
|---|---|
| Median reaction (30-min) | -0.01% |
| Measured reactions | 1,208 |
Half of all Biogen Inc. news events land between -0.58% and +0.61% at 30 minutes.
Reaction stats as of 2026-09-21. Newest measured event . Reaction = percent move vs. the price at the news timestamp.
How BIIB reacts, by analyst action.
| Event | Events | Median 30-min | % positive | Median to close |
|---|---|---|---|---|
| Analyst upgrades | 36 | +0.44% | 61% | +0.64% |
| Analyst downgrades | 44 | -0.27% | 41% | -0.44% |
| Coverage initiations | 20 | +0.11% | 55% | -0.69% |
| Rating reiterations | 258 | -0.16% | 38% | -0.19% |
| Price-target raises | 54 | -0.03% | 48% | -0.44% |
| Price-target cuts | 69 | +0.11% | 58% | +0.13% |
Last 3 years, pulled 2026-09-21. Reaction = percent move vs. the price at the news timestamp. Counts and medians only. The same measurement runs across every name in the dataset. See how BIIB ranks against every other measured name →
That’s how BIIB usually reacts — get an email when it moves on news →Email me when BIIB moves on news.
One email per qualifying move — the headline, the measured reaction, and how it compares to BIIB's baseline. Nothing else.
Recent BIIB events, each with its measured reaction.
| Date | Headline | Event | Source | 5-min | To close |
|---|---|---|---|---|---|
| Phase 3 Pediatric EMPAVELI Data Published in Clinical Journal of the American Society of Nephrology Show Reduction in Proteinuria and Stabilized Kidney Function in Adolescents with C3G or Primary IC-MPGN | Press release | GlobeNewswire | +0.51% | -1.62% | |
| Stoke Therapeutics and Biogen Present Long-Term Clinical Data that Support the Disease-Modifying Potential of Zorevunersen, an Investigational Medicine for the Treatment of Dravet Syndrome, at the 16th European Epilepsy Congress (EEC) | Press release | GlobeNewswire | +0.73% | -0.14% | |
| LEQEMBI IQLIK®(lecanemab-irmb) Autoinjector for Initiation of Therapy Now Available in the U.S. for Early Alzheimer's Disease | Press release | PR Newswire | -0.40% | +0.80% | |
| Biogen Completes Acquisition of RayThera Inc. | Press release | GlobeNewswire | -0.83% | +0.27% | |
| Form 10-Q BIOGEN INC. For: Jun 30 | SEC filing · Form 10-Q | SEC EDGAR | +1.99% | -0.60% | |
| Form 8-K BIOGEN INC. For: Jul 29 | SEC filing · Form 8-K | SEC EDGAR | +1.99% | -0.60% | |
| Synapticure Launches Groundbreaking Ataxia Care Program, Expanding Access to Specialized Neurology Nationwide | Press release | PR Newswire | -1.14% | +5.38% | |
| Biogen Presents Phase 2 CELIA Data at AAIC Demonstrating Meaningful Clinical Outcomes and Robust Tau Reduction with Diranersen in Early Alzheimer’s Disease | Press release | GlobeNewswire | -0.68% | -3.88% | |
| LEQEMBI® Real-World LEADER Study Presented at AAIC® 2026 Finds Over 75% of Early Alzheimer's Patients Enrolled in the Study Remained Stable and Nearly 7% Improved Over an Average of 17 Months of Treatment | Press release | PR Newswire | +0.18% | +0.72% | |
| FDA Approves LEQEMBI IQLIK® (lecanemab-irmb) Subcutaneous Injection as an Initiation Dose for Early Alzheimer's Disease | Press release | PR Newswire | -0.68% | -3.88% | |
| LEQEMBI® Subcutaneous Autoinjector Clinical Data Supports Similar Efficacy and Safety to IV Formulation in Early Alzheimer's Disease Presented at the Alzheimer's Association International Conference® (AAIC®) 2026 | Press release | PR Newswire | -0.80% | +4.87% | |
| Form 8-K BIOGEN INC. For: Jul 01 | SEC filing · Form 8-K | SEC EDGAR | -0.28% | +1.82% | |
| Biogen to Highlight Breadth of Alzheimer’s Disease Portfolio at AAIC 2026, Including Phase 2 CELIA Data for Diranersen | Press release | GlobeNewswire | +0.56% | +0.75% | |
| Bronstein, Gewirtz & Grossman, LLC Is Investigating Biogen Inc. (BIIB) And Encourages Shareholders to Connect | Press release | ACCESS Newswire | -0.20% | -0.06% | |
| Bronstein, Gewirtz & Grossman, LLC Initiates an Investigation into Allegations Against Biogen Inc. (BIIB) And Encourages Shareholders to Reach Out | Press release | ACCESS Newswire | -0.20% | -0.06% | |
| Bronstein, Gewirtz & Grossman, LLC Announces an Investigation Against Biogen Inc. (BIIB) and Encourages Shareholders to Learn More About the Investigation | Press release | ACCESS Newswire | +0.10% | +1.24% | |
| Biogen Inc. (BIIB) Investigation: Bronstein, Gewirtz & Grossman, LLC Encourages Shareholders to Contact the Firm to Learn More About the Investigation | Press release | ACCESS Newswire | +0.02% | -0.09% | |
| Bronstein, Gewirtz & Grossman, LLC Encourages Biogen Inc. (BIIB) Stockholders to Inquire about Securities Investigation | Press release | ACCESS Newswire | -0.03% | -1.33% | |
| Bronstein, Gewirtz & Grossman, LLC Is Investigating Biogen Inc. (BIIB) And Encourages Stockholders to Connect | Press release | ACCESS Newswire | -0.04% | -2.65% | |
| Form 8-K BIOGEN INC. For: Jun 09 | SEC filing · Form 8-K | SEC EDGAR | -0.34% | +2.29% | |
| Form 8-K/A BIOGEN INC. For: May 14 | SEC filing · Form 8-K | SEC EDGAR | -0.34% | +2.29% | |
| Biogen Inc. (BIIB) Investigation: Bronstein, Gewirtz & Grossman, LLC Encourages Stockholders to Contact the Firm to Learn More About the Investigation | Press release | ACCESS Newswire | -0.01% | +1.85% | |
| Bronstein, Gewirtz & Grossman, LLC Announces an Investigation Against Biogen Inc. (BIIB) and Encourages Stockholders to Learn More About the Investigation | Press release | ACCESS Newswire | +0.08% | -1.62% | |
| Bronstein, Gewirtz & Grossman, LLC Encourages Biogen Inc. (BIIB) Investors to Inquire about Securities Investigation | Press release | ACCESS Newswire | +0.24% | -2.71% | |
| BIIB SHAREHOLDER INVESTIGATION: SueWallSt Investigates Biogen Inc. for Possible Securities Law Violations | Press release | PR Newswire | -0.24% | +0.34% | |
| Form 8-K BIOGEN INC. For: May 14 | SEC filing · Form 8-K | SEC EDGAR | -0.04% | -4.43% | |
| CNS Drug Delivery Breakthroughs Unlock Significant Biotech Market Opportunities | Press release | GlobeNewswire | +1.30% | +1.64% | |
| Update on FDA Priority Review of LEQEMBI® IQLIK™ (lecanemab-irmb) Subcutaneous Injection as a Starting Dose for Early Alzheimer's Disease | Press release | PR Newswire | +1.05% | +1.99% | |
| Jeito Capital Bolsters Its Leadership Team With the Appointment of Elaine Caughey, MBA, as Partner, Business Development and Investor Relations, and Sarah Shackelton, MPA, as Partner, Talent | Press release | Business Wire | +0.44% | +0.93% | |
| Form 10-Q BIOGEN INC. For: Mar 31 | SEC filing · Form 10-Q | SEC EDGAR | +3.54% | +6.59% | |
| Form 8-K BIOGEN INC. For: Apr 29 | SEC filing · Form 8-K | SEC EDGAR | +3.54% | +6.59% | |
| Form ARS BIOGEN INC. For: Dec 31 | SEC filing · Form ARS | SEC EDGAR | +3.54% | +6.59% | |
| Form DEF 14A BIOGEN INC. For: Jun 09 | SEC filing · Form DEF | SEC EDGAR | +3.54% | +6.59% | |
| Form DEFA14A BIOGEN INC. | SEC filing · Form DEFA14A | SEC EDGAR | +3.54% | +6.59% | |
| TJ Biopharma Enters into Agreement with Biogen for Felzartamab Assets in the Greater China Region | Press release | PR Newswire | +0.13% | +2.12% | |
| Form 8-K BIOGEN INC. For: Apr 06 | SEC filing · Form 8-K | SEC EDGAR | -0.33% | -2.63% | |
| Form 8-K BIOGEN INC. For: Mar 31 | SEC filing · Form 8-K | SEC EDGAR | -0.61% | +0.33% | |
| Biogen Announces Second Positive Phase 2 Litifilimab Trial in Cutaneous Lupus Erythematosus at 2026 American Academy of Dermatology Annual Meeting, Showing a Significant Reduction in Skin Disease Activity | Press release | GlobeNewswire | +0.24% | +0.76% | |
| Results from Real-World, Long-Term Treatment Persistence with LEQEMBI® (lecanemab-irmb) in the United States Presented at AD/PD™ 2026 | Press release | PR Newswire | -0.10% | -0.66% | |
| Biogen to Present New Late-Breaking Litifilimab Phase 2 AMETHYST Data in Cutaneous Lupus Erythematosus at 2026 American Academy of Dermatology Annual Meeting | Press release | GlobeNewswire | +0.48% | +0.68% | |
| Form 8-K BIOGEN INC. For: Mar 11 | SEC filing · Form 8-K | SEC EDGAR | -0.99% | -1.58% | |
| Form 8-K BIOGEN INC. For: Feb 11 | SEC filing · Form 8-K | SEC EDGAR | +0.41% | +2.81% | |
| Form 10-K BIOGEN INC. For: Dec 31 | SEC filing · Form 10-K | SEC EDGAR | +2.34% | +7.58% | |
| Form 8-K BIOGEN INC. For: Feb 06 | SEC filing · Form 8-K | SEC EDGAR | +2.34% | +7.58% | |
| FDA Accepts LEQEMBI® IQLIKTM (lecanemab-irmb) Supplemental Biologics License Application as a Subcutaneous Starting Dose for the Treatment of Early Alzheimer's Disease under Priority Review | Press release | PR Newswire | -0.21% | +0.84% | |
| Form 8-K BIOGEN INC. For: Jan 13 | SEC filing · Form 8-K | SEC EDGAR | -1.38% | -4.74% | |
| Eisai Presents New Data on the Continued and Expanding Benefit of LEQEMBI® (lecanemab-irmb) Maintenance Treatment in Early Alzheimer's Disease at the Clinical Trials on Alzheimer's Disease (CTAD) Conference 2025 | Press release | PR Newswire | -0.22% | +0.07% | |
| New Data Presented at the Clinical Trials on Alzheimer's Disease (CTAD) Conference 2025 Confirms Pharmacological Effect of LEQEMBI® (lecanemab-irmb) on Neurotoxic Aß Protofibrils in CSF | Press release | PR Newswire | -0.61% | +0.32% | |
| Eisai Completes Rolling Submission to U.S. FDA for LEQEMBI® IQLIK™ (lecanemab-irmb) Supplemental Biologics License Application as a Subcutaneous Starting Dose for the Treatment of Early Alzheimer's Disease Under Fast Track Status | Press release | PR Newswire | +1.01% | +2.76% | |
| Biogen to Highlight New Lecanemab Data and Scientific Advances at the 18th Clinical Trials on Alzheimer’s Disease Conference | Press release | GlobeNewswire | -0.19% | +0.02% |
Each reaction is the move the market actually made, measured from the news timestamp. Headlines link through to the BIIB section they belong to.
Where else BIIB is measured.
BIIB earnings → · Analyst actions → · SEC filings →
Other Healthcare names, measured the same way
| Ticker | Events | Median 30-min | % positive |
|---|---|---|---|
| Orthofix Medical Inc. (OFIX) | 1,217 | +0.06% | 51% |
| IMMUNOMEDICS (IMMU) | 1,213 | -0.08% | 45% |
| Rocket Pharmaceuticals, Inc. (RCKT) | 1,202 | -0.02% | 47% |
| Insulet Corporation (PODD) | 1,198 | +0.14% | 55% |
Same sector, same measurement: percent move vs. the price at the news timestamp, read at 30 minutes. Sample sizes differ, so the medians are comparable but the confidence behind them is not.
All Healthcare names, measured the same way →
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Every name we’ve measured, in one place.
How the numbers are made.
How is Biogen Inc.'s median reaction calculated?
Every labeled BIIB news event is measured from its own timestamp: the last trade before the news is the base price, and the move is read at fixed horizons — 30 minutes of trading, then the close. The median across 1,208 events is what this page reports. Point-in-time, zero look-ahead: no event borrows information from a later one.
What counts as a positive reaction?
Any event whose price move is above zero at the horizon, relative to the last trade before the news timestamp. 49% of BIIB's measured events are up at 30 minutes; the rest close the window flat or negative.
How often is this page updated?
The news table refreshes automatically as new events are labeled and priced. The reaction medians are re-pulled in batches from the dataset — the figures here are as of 2026-09-21.
Does BIIB's past reaction predict its next one?
No. These are realized facts about past events, not forecasts. They describe a distribution — they say nothing certain about any future move.