BIIB
Moving with its group (XLV +2.5%)
- BIIB +2.58% on the last session vs SPY +0.12%: +2.5 pts of stock-specific move.
- The health care ETF (XLV) +2.5% (+2.4 pts vs SPY): the stock moved with its group.
- Aftermath, big gain (+2.6% today so far, past its big-gain line of +2.5%): After its 73 big gains in the past 5 years, BIIB was higher a month later 28 times out of 73; half the outcomes fell between -4.4% and +5.8%. History, not a forecast.
- 2 analyst actions in the past 10 days (1 positive, 1 negative); latest: UBS maintained Buy, raised target $240 → $270.
- 1 insider or congressional trade in the past 30 days.
- Market backdrop (Today): Core PPI m/m 1.3% vs 0.3% expected (hotter); Core Retail Sales m/m 0.9% vs 0.6% expected (stronger); S&P futures -0.08%, 10-year yield -3bp in the 30 minutes after.
Bargain & stretch prices
Prices BIIB only reaches with set odds, from its own recent swings. Odds, not a forecast.
| Today | Next 5 sessions | |
|---|---|---|
| Stretch sell side |
236.50 +1.6% ↓ less often after a new 52-week high
reached 3 in 10 days · 25% vs usual 28% reached today |
241.11 +3.6% ↓ less often after a new 52-week high
reached 3 in 10 weeks · 27% vs usual 30% |
| Now | 238.83 · prior close 232.83 | |
| Bargain buy side |
229.22 -1.6% reached 3 in 10 days |
224.84 -3.4% reached 3 in 10 weeks |
More patient or more eager
| Bargain | Reached | Stretch | Reached | |
|---|---|---|---|---|
| Today | ||||
| Patient | 228.06 | 2 in 10 days | 237.70 | 2 in 10 days↓ 15% vs 17% |
| Balanced | 229.22 | 3 in 10 days | 236.50 | 3 in 10 days↓ 25% vs 28% |
| Eager | 230.31 | 4 in 10 days | 235.38 | 4 in 10 days↓ 43% vs 45% |
| Next 5 sessions | ||||
| Patient | 222.30 | 2 in 10 weeks | 243.86 | 2 in 10 weeks↓ 16% vs 19% |
| Balanced | 224.84 | 3 in 10 weeks | 241.11 | 3 in 10 weeks↓ 27% vs 30% |
| Eager | 227.23 | 4 in 10 weeks | 238.57 | 5 in 10 weeks↓ 45% vs 48% |
"3 in 10 days" means the price was reached on about 3 of every 10 days like this one. Patient prices are further away and come less often; eager ones are closer and come more often. From BIIB's daily swings (about 1.6% a day lately), anchored on the Oct 14 close. The odds were measured on 10 years of S&P 500 prices (they move about 3 points from year to year with the market: bargain prices come more often in falling years, stretch prices in rising ones), and where a situation below changed them consistently (in at least 8 of 10 years), they are adjusted and marked. In those tests, waiting for the bargain price did no better on average than buying at the close: what you save when it comes, you pay when it doesn't.
Situations on the Oct 14 close
- Stretch price, next session: reached 25% of days instead of the usual 28% (held in 10 of 10 years)
- Stretch price, next 5 sessions: reached 27% of weeks instead of the usual 30% (held in 9 of 10 years)
| Date | That day | 1 week on | 1 month on | 3 months on |
|---|---|---|---|---|
| Sep 22, 2026 | +2.9% | +0.8% | — | — |
| Aug 19, 2026 | +4.2% | -0.2% | -2.7% | — |
| Jun 26, 2026 | +7.0% | -3.5% | -4.8% | +5.4% |
| May 13, 2026 | +2.6% | -8.2% | -2.2% | +3.0% |
| Feb 6, 2026 | +8.5% | -2.3% | -6.3% | -3.8% |
| Jan 6, 2026 | +4.6% | -2.4% | +1.5% | -1.5% |
| Nov 18, 2025 | +2.5% | +7.8% | +0.6% | +13.7% |
| May 1, 2023 | +2.3% | +1.0% | -4.7% | -13.4% |
Big drop and big gain: among BIIB's own worst or best 10% of daily moves, as on the Aftermath tab. The past times are history: in our tests, how a stock did after its earlier times did not predict the next one, and across the S&P 500 none of these situations leaned up or down except, weakly, an all-time high followed by a big drop. Not advice.
Price ladder
| All-time closing high Mar 20, 2015 |
475.98 +99.3% |
| Highest analyst target | 300.00 +25.6% |
| Stretch, next 5 sessions | 241.11 +1.0% |
| Mean analyst target | 239.18 +0.1% |
| Now | 238.83 |
| 52-week closing high Oct 15, 2026 |
238.83 0.0% |
| Previous close Oct 14, 2026 |
232.83 -2.5% |
| Bargain, next 5 sessions | 224.84 -5.9% |
| 50-day average | 219.25 -8.2% |
| 200-day average | 197.56 -17.3% |
| Lowest analyst target | 175.00 -26.7% |
| 52-week closing low Oct 16, 2025 |
142.26 -40.4% |
Closing prices (all-time = the 35 years Yahoo has). Percentages are the distance from now. These are levels people watch, not levels the price has to respect. Not advice.