BIIB
Underperforming without a clear catalyst yet
- BIIB −1.32% on the last session vs SPY +0.74%: −2.1 pts of stock-specific move.
- Market backdrop (Fri): Average Hourly Earnings m/m 0.1% vs 0.3% expected (cooler); Non-Farm Employment Change 29K vs 89K expected (weaker); S&P futures +0.41%, 10-year yield -5bp in the 30 minutes after.
After each kind of event
| Event | Events | 1 day | 1 week | 1 month | 1 quarter |
|---|---|---|---|---|---|
| Any day | 1,255 | -0.1%#495 H | 0.0%#461 H | -1.1%#495 H | -1.5%#420 M |
| Big drop (-2.3% or worse) | 64 | +0.1%#308 H | 0.0%#442 H | -1.2%#499 H | +0.9%#299 M |
| Big gain (+2.4% or better) | 75 | -0.2%#477 H | -1.0%#455 H | -1.2%#493 H | +2.1%#299 M |
| Earnings beat | 18 | +0.4%#218 M | -0.6%#442 M | +3.3%#81 M | +4.0%#182 M |
| Earnings miss | 2 | -0.2%– | -3.8%– | -3.3%– | +2.0%– |
| 52-week high | 9 | -0.6%#312 M | -0.7%#371 M | -2.5%#467 M | +3.0%#176 L |
| 52-week low | 9 | -0.5%#210 M | -0.9%#205 M | -6.1%#258 M | +0.9%#163 L |
| Crossed above 200-day avg | 4 | -2.1%#420 L | -3.2%#469 L | -1.9%#311 L | +8.8%#197 L |
| Crossed below 200-day avg | 4 | +0.8%#217 L | +0.3%#258 L | -1.9%#341 L | +11.5%#186 L |
| RSI oversold | 15 | +0.2%#209 M | +0.8%#197 M | -1.4%#473 M | -5.0%#474 M |
| RSI overbought | 9 | +0.2%#224 M | -2.4%#451 M | -1.5%#486 M | -3.8%#365 M |
| Reddit spike | — | — | — | — | — |
| Analyst upgrade | — | — | — | — | — |
| Analyst downgrade | — | — | — | — | — |
| Insider buy | — | — | — | — | — |
| Insider unplanned sale | — | — | — | — | — |
Median gain from the close of the session the event was known, over each holding period; #rank among the S&P 500 stocks after the same kind of event (#1 = best). "Big" is BIIB's own: its worst / best 10% of days over the prior 2 years. Highlighted: happening in the latest session.
Big gain (+2.4% or better)
A daily rise among the stock's own best 10% of the prior 2 years.
| Holding | Events | Median (likely range) | Confidence | Rank | Up | vs SPY | Range of outcomes (worst · 25–75% · median · best) | vs S&P 500 stocks (their medians) |
|---|---|---|---|---|---|---|---|---|
| 1 day | 75 | -0.19% (-0.3 to 0.0) | High | #477 of 500 | 44% | -0.28% |
-8%
+2%
|
|
| 1 week | 75 | -0.97% (-1.5 to +0.3) | High | #455 of 500 | 45% | -1.81% |
-10%
+7%
|
|
| 1 month | 74 ≈39 indep. | -1.20% (-2.4 to -0.3) | High | #493 of 500 | 39% | -2.67% |
-19%
+19%
|
|
| 1 quarter | 70 ≈15 indep. | +2.06% (-3.8 to +5.8) | Medium | #299 of 499 | 53% | -4.92% |
-25%
+27%
|
Range of outcomes: all of BIIB's big gains in the past 5 years, from the worst to the best result over each holding period; the box holds the middle half, the tick is the median. A wide box means the median alone says little. Hover the median for the average.
Big gain by trend
| When it happened | Events | 1 day | 1 week | 1 month | 1 quarter |
|---|---|---|---|---|---|
| Long trendAbove its 200-day avg now | 36 | +0.1%H vs 0.0% | -0.3%H vs +0.4% | 0.0%M vs +2.2% | +6.8%L vs +5.6% |
| Below its 200-day avg | 39 | -0.3%H vs -0.1% | -1.2%H vs -0.3% | -2.4%H vs -2.8% | -6.5%M vs -6.4% |
| Medium trendAbove its 50-day avg now | 47 | +0.2%H vs -0.1% | -1.0%H vs +0.1% | -1.2%H vs 0.0% | +4.2%M vs +3.7% |
| Below its 50-day avg | 28 | -0.7%H vs 0.0% | -0.9%H vs -0.1% | -1.2%H vs -1.9% | -1.7%M vs -3.4% |
| Short trendAbove its 20-day avg | 50 | +0.1%H vs -0.1% | -1.3%H vs -0.4% | -0.5%H vs 0.0% | +3.6%M vs +2.8% |
| Below its 20-day avg now | 25 | -0.6%H vs 0.0% | 0.0%H vs +0.1% | -2.4%H vs -1.9% | -4.8%M vs -4.6% |
The same event split by where BIIB stood against its 200-, 50- and 20-day averages when it happened (a dip in an uptrend vs a falling knife); "vs" is the plain any-day median in that trend; "now" marks where it stands today. Splitting halves the evidence, so watch the confidence letters: H / M / L.
Latest big gains
| Event | Entry | 1 day | 1 week | 1 month | 1 quarter | |
|---|---|---|---|---|---|---|
| Sep 22, 2026 | Sep 22 @ $225.36 | +2.9% on the day (line +2.4%) | +1.0% | +0.8% | … | … |
| Sep 2, 2026 | Sep 2 @ $222.67 | +3.1% on the day (line +2.4%) | +0.8% | -3.3% | -1.3% | … |
| Aug 12, 2026 | Aug 12 @ $208.87 | +2.4% on the day (line +2.4%) | +0.9% | +6.1% | +4.0% | … |
| Jul 28, 2026 | Jul 28 @ $205.61 | +2.7% on the day (line +2.3%) | +1.8% | +1.4% | +7.5% | … |
| Jul 13, 2026 | Jul 13 @ $209.03 | +5.0% on the day (line +2.3%) | -8.2% | -4.3% | -2.5% | … |
| Jun 26, 2026 | Jun 26 @ $216.03 | +7.0% on the day (line +2.2%) | +0.3% | -3.5% | -4.8% | +5.4% |
| Jun 11, 2026 | Jun 11 @ $199.96 | +2.9% on the day (line +2.2%) | 0.0% | -1.7% | -4.0% | +8.6% |
| Jun 3, 2026 | Jun 3 @ $195.96 | +3.8% on the day (line +2.2%) | +0.2% | -0.9% | +6.4% | +13.6% |
| May 22, 2026 | May 22 @ $193.76 | +2.3% on the day (line +2.2%) | -0.4% | -0.8% | +3.0% | +12.6% |
| May 11, 2026 | May 11 @ $197.95 | +2.3% on the day (line +2.2%) | +0.7% | -3.1% | -1.9% | +3.0% |
| Apr 29, 2026 | Apr 29 @ $194.38 | +6.0% on the day (line +2.2%) | -2.6% | -1.9% | +0.8% | +7.0% |
| Apr 20, 2026 | Apr 20 @ $183.34 | +3.4% on the day (line +2.2%) | +1.4% | -1.5% | +3.9% | +10.8% |
| Apr 8, 2026 | Apr 8 @ $179.90 | +2.4% on the day (line +2.2%) | -1.6% | +0.4% | +6.4% | +10.6% |
| Mar 25, 2026 | Mar 25 @ $189.18 | +2.9% on the day (line +2.2%) | +1.0% | -2.9% | -2.5% | +6.8% |
| Mar 4, 2026 | Mar 4 @ $189.94 | +3.2% on the day (line +2.2%) | -1.0% | +0.3% | -6.6% | +3.2% |
Aftermath: entry is the close of the first session the event was fully known (the same session for price moves, the reaction session for earnings, the next session for Reddit, analyst and insider events, which are dated by day). Repeats within a few sessions count as one event. Past performance after an event says nothing certain about the next one. Not advice.