BIIB options analytics
BIIB · Stock
Data as of 6 November 2026 (end of day)
BIIB options are pricing a 30-day at-the-money volatility of 48.8%, a move of about ±14.0% over the next month. Its history here is 325 sessions, short of the 180 a percentile needs, so this reading is not yet ranked against its own past.
Its 25-delta puts carry 1.38 volatility points more than the calls.
The term structure is inverted: 90-day volatility is 6% below 30-day, which happens when the market prices something dated into the nearer expirations.
Its next earnings report is 2027-01-27 (estimated from its reporting cadence).
Across its last 7 reports the options market priced an average move of ±6.2% and BIIB moved 11.7% on average, staying inside the priced band 6 times out of 7.
Current readings
- 30-day ATM implied volatilityⓘ
- 48.77%
- 25-delta risk reversalⓘ
- +1.38
- 25-delta butterflyⓘ
- +0.02
- Term structure slopeⓘ
- 0.938
Prices a move of about ±14.0% over 30 days, or ±3.1% on a typical day.
Puts carry 1.38 volatility points more than calls the same distance from the money.
The wings carry about the same volatility as at-the-money.
90-day volatility is 6% below 30-day.
Where 30-day implied volatility sits
Against 113 prior sessions (one-year window)
Not enough history in this window to place the current reading.
- IV percentile, 1 year
- —
- IV rank, 1 year
- —
- IV percentile, 2 years
- —
- IV rank, 2 years
- —
Rank is the position between the lowest and highest readings in the window, so a single past extreme pins everything after it near one end. Percentile is the share of sessions below the current reading and is unaffected by how far that extreme reached. Both are withheld when the window holds fewer than 180 sessions.
Session detail
- Underlying close
- $248.35
- 30-day implied forward
- $250.09
- 60-day ATM IV
- 48.28%
- 90-day ATM IV
- 45.76%
- 180-day ATM IV
- 42.88%
- Expirations used
- 6
- Total open interest
- 36,297
- Put / call open interest
- 0.46
The forward is derived from put-call parity on the strikes nearest the money, not taken from the underlying close. It is what every moneyness and delta on this page is measured against.
30-day at-the-money implied volatility
Last 325 sessions
Show the underlying numbers (most recent 120)
| Session | 30-day ATM IV | 25-delta RR | Term slope | Close |
|---|---|---|---|---|
| 2026-11-06 | 48.77% | +1.38 | 0.938 | $248.35 |
| 2026-11-05 | 48.63% | +1.37 | 0.930 | $243.93 |
| 2026-11-04 | 47.53% | +5.44 | 0.920 | $254.46 |
| 2026-11-03 | — | — | — | $248.93 |
| 2026-11-02 | 44.38% | -0.33 | 0.947 | $249.01 |
| 2026-10-30 | 44.91% | +1.32 | 0.943 | $253.62 |
| 2026-10-29 | 40.92% | +0.61 | 1.005 | $249.65 |
| 2026-10-28 | 38.47% | +0.99 | 1.089 | $244.05 |
| 2026-10-27 | 44.96% | +5.69 | 0.914 | $252.73 |
| 2026-10-26 | 48.07% | +4.11 | 0.908 | $252.26 |
| 2026-10-23 | 45.40% | +4.66 | 0.951 | $250.69 |
| 2026-10-22 | 44.87% | +6.55 | 0.925 | $253.84 |
| 2026-10-21 | 42.22% | +2.62 | 0.941 | $240.98 |
| 2026-10-20 | 43.60% | +2.48 | 0.923 | $243.10 |
| 2026-10-19 | — | — | — | $233.48 |
| 2026-10-16 | — | — | — | $232.65 |
| 2026-10-15 | — | — | — | $235.35 |
| 2026-10-14 | — | — | — | $232.83 |
| 2026-10-13 | — | — | — | $228.90 |
| 2026-10-09 | — | — | — | $225.71 |
| 2026-10-08 | — | — | — | $218.43 |
| 2026-10-07 | — | — | — | $222.15 |
| 2026-10-06 | — | — | — | $222.89 |
| 2026-10-05 | — | — | — | $223.59 |
| 2026-10-02 | — | — | — | $219.88 |
| 2026-10-01 | — | — | — | $222.82 |
| 2026-09-30 | — | — | — | $225.88 |
| 2026-09-29 | 32.02% | +0.73 | 1.148 | $227.07 |
| 2026-09-28 | — | — | — | $228.69 |
| 2026-09-25 | — | — | — | $227.60 |
| 2026-09-24 | — | — | — | $226.36 |
| 2026-09-23 | — | — | — | $227.53 |
| 2026-09-22 | 32.96% | +2.78 | 1.144 | $225.36 |
| 2026-09-21 | — | — | — | $219.07 |
| 2026-09-18 | 35.83% | +3.14 | 1.035 | $215.50 |
| 2026-09-17 | — | — | — | $219.05 |
| 2026-09-16 | — | — | — | $216.01 |
| 2026-09-15 | — | — | — | $216.17 |
| 2026-09-14 | — | — | — | $217.36 |
| 2026-09-11 | — | — | — | $217.15 |
| 2026-09-10 | — | — | — | $215.43 |
| 2026-09-09 | — | — | — | $210.73 |
| 2026-09-08 | — | — | — | $212.50 |
| 2026-09-04 | — | — | — | $220.83 |
| 2026-09-03 | — | — | — | $224.51 |
| 2026-09-02 | — | — | — | $222.67 |
| 2026-09-01 | — | — | — | $216.04 |
| 2026-08-31 | — | — | — | $216.65 |
| 2026-08-28 | — | — | — | $218.50 |
| 2026-08-27 | — | — | — | $221.50 |
| 2026-08-26 | — | — | — | $221.07 |
| 2026-08-25 | — | — | — | $220.77 |
| 2026-08-24 | — | — | — | $218.12 |
| 2026-08-21 | — | — | — | $216.78 |
| 2026-08-20 | — | — | — | $214.35 |
| 2026-08-19 | — | — | — | $221.56 |
| 2025-09-29 | 40.23% | -2.32 | 0.979 | $138.52 |
| 2025-09-26 | 36.42% | +0.71 | 1.050 | $137.37 |
| 2025-09-25 | — | — | — | $135.67 |
| 2025-09-24 | 36.43% | +1.34 | 1.044 | $137.67 |
| 2025-09-23 | 34.16% | +1.56 | 1.082 | $139.31 |
| 2025-09-22 | 34.44% | +0.54 | 1.064 | $140.66 |
| 2025-09-19 | 33.93% | -1.44 | 1.084 | $142.50 |
| 2025-09-18 | — | — | — | $143.81 |
| 2025-09-17 | 32.07% | +3.14 | 1.114 | $144.87 |
| 2025-09-16 | — | — | — | $143.68 |
| 2025-09-15 | — | — | — | $143.32 |
| 2025-09-12 | — | — | — | $144.86 |
| 2025-09-11 | — | — | — | $148.84 |
| 2025-09-10 | — | — | — | $142.61 |
| 2025-09-09 | 31.68% | +2.46 | 1.079 | $143.60 |
| 2025-09-08 | 29.46% | +2.20 | 1.175 | $141.35 |
| 2025-09-05 | 33.49% | +2.99 | 1.071 | $140.67 |
| 2025-09-04 | 31.43% | +1.27 | 1.074 | $139.94 |
| 2025-09-03 | 30.97% | +1.31 | 1.114 | $141.62 |
| 2025-09-02 | 31.81% | +3.51 | 1.077 | $139.63 |
| 2025-08-29 | 32.06% | +0.66 | 1.058 | $132.22 |
| 2025-08-28 | 34.12% | -2.13 | 0.993 | $132.65 |
| 2025-08-27 | 34.42% | -0.30 | 0.989 | $136.36 |
| 2025-08-26 | 31.32% | +1.41 | 1.043 | $136.72 |
| 2025-08-25 | 31.16% | +0.75 | 1.071 | $136.36 |
| 2025-08-22 | 30.39% | +0.51 | 1.072 | $139.31 |
| 2025-08-21 | 33.66% | +3.84 | 1.006 | $139.12 |
| 2025-08-20 | 33.81% | -0.88 | 0.992 | $138.99 |
| 2025-08-19 | 33.65% | -0.87 | 1.004 | $138.86 |
| 2025-08-18 | 31.69% | +0.61 | 1.069 | $135.91 |
| 2025-08-15 | — | — | — | $138.60 |
| 2025-08-14 | 31.55% | +0.40 | 1.058 | $134.94 |
| 2025-08-13 | — | — | — | $135.19 |
| 2025-08-12 | — | — | — | $128.93 |
| 2025-08-11 | — | — | — | $128.00 |
| 2025-08-08 | 32.35% | +1.19 | 1.044 | $130.67 |
| 2025-08-07 | — | — | — | $127.75 |
| 2025-08-06 | 33.68% | -0.30 | 1.014 | $129.34 |
| 2025-08-05 | — | — | — | $132.89 |
| 2025-08-04 | 34.03% | +2.88 | 1.000 | $132.20 |
| 2025-08-01 | 34.91% | +2.13 | 1.000 | $131.95 |
| 2025-07-31 | — | — | — | $128.00 |
| 2025-07-30 | 37.79% | +2.17 | 0.936 | $126.64 |
| 2025-07-29 | — | — | — | $127.90 |
| 2025-07-28 | — | — | — | $129.28 |
| 2025-07-25 | — | — | — | $131.52 |
| 2025-07-24 | 38.52% | +2.37 | 0.936 | $132.59 |
| 2025-07-23 | 38.81% | +0.40 | 0.929 | $130.98 |
| 2025-07-22 | 42.57% | +0.20 | 0.842 | $127.85 |
| 2025-07-21 | — | — | — | $122.68 |
| 2025-07-18 | — | — | — | $124.99 |
| 2025-07-17 | — | — | — | $128.69 |
| 2025-07-16 | — | — | — | $128.46 |
| 2025-07-15 | — | — | — | $127.50 |
| 2025-07-14 | — | — | — | $133.11 |
| 2025-07-11 | — | — | — | $134.21 |
| 2025-07-10 | — | — | — | $135.33 |
| 2025-07-09 | — | — | — | $133.02 |
| 2025-07-08 | — | — | — | $134.46 |
| 2025-07-07 | — | — | — | $130.13 |
| 2025-07-03 | — | — | — | $132.87 |
| 2025-07-02 | — | — | — | $133.19 |
| 2025-07-01 | — | — | — | $130.07 |
| 2025-06-30 | — | — | — | $125.59 |
The chart covers every session in the archive, 325 in total. The table lists the most recent 120.
25-delta risk reversal
Last 325 sessions
The dashed line marks zero, where the 25-delta put and call carry the same implied volatility.
Skew curve
Implied volatility by delta, front expirations
Implied volatility by delta
14d (2026-11-20) · 42d (2026-12-18) · 133d (2027-03-19)
The axis is call delta. Readings to the right of the dashed centre line are taken from the out-of-the-money put at that strike, which is the contract whose quote the volatility was solved from. Points are only plotted where surviving quotes bracket the delta on both sides; nothing is extrapolated past the last traded strike.
Show the underlying numbers
| Delta | 14d | 42d | 133d |
|---|---|---|---|
| 20Δ call | — | 49.99% | — |
| 25Δ call | 36.56% | 50.57% | 42.76% |
| 30Δ call | 36.22% | 50.25% | 42.12% |
| 35Δ call | 36.95% | 50.16% | 43.00% |
| 40Δ call | 35.29% | 51.45% | 43.37% |
| 45Δ call | 37.53% | 52.05% | 43.92% |
| ATM | 36.76% | 51.34% | 44.06% |
| 45Δ put | 37.39% | 52.03% | 44.18% |
| 40Δ put | 37.75% | 52.39% | 44.35% |
| 35Δ put | 37.86% | 52.06% | 44.70% |
| 30Δ put | 37.98% | 51.32% | 45.18% |
| 25Δ put | 38.32% | 51.89% | 45.58% |
| 20Δ put | — | 50.68% | — |
Wing readings by expiration
| Expiration | Days | Forward | ATM IV | 25Δ put | 25Δ call | RR | Butterfly | Quotes |
|---|---|---|---|---|---|---|---|---|
| 2026-11-20 | 14 | $249.80 | 36.76% | 38.32% | 36.56% | +1.76 | +0.68 | 9 |
| 2026-12-18 | 42 | $250.30 | 51.34% | 51.89% | 50.57% | +1.32 | -0.11 | 16 |
| 2027-03-19 | 133 | $252.54 | 44.06% | 45.58% | 42.76% | +2.82 | +0.11 | 12 |
| 2027-04-16 | 161 | $253.68 | 43.28% | 44.59% | 41.41% | +3.18 | -0.28 | 11 |
| 2027-06-17 | 223 | $255.08 | 42.22% | 44.23% | 40.34% | +3.88 | +0.06 | 14 |
| 2027-09-17 | 315 | $257.93 | 40.72% | 42.31% | 39.19% | +3.12 | +0.03 | 19 |
Each curve above is one expiration. The vertical position is implied volatility; the horizontal position is the delta of the contract it was read from. For US equities the curve normally slopes upward to the right, meaning out-of-the-money puts carry higher implied volatility than equidistant calls.
The 25-delta risk reversal summarises that slope as a single number: the 25-delta put volatility minus the 25-delta call volatility. The butterfly summarises the curvature: the average of the two wings minus the at-the-money reading.
Term structure
At-the-money implied volatility by expiration
At-the-money implied volatility by expiration
6 listed expirations produced a usable reading
The horizontal axis is the square root of days to expiration, which is the scale volatility lives on. A curve that is flat in variance terms plots as a straight line here rather than bending sharply through the front week.
Show the underlying numbers
| Expiration | Days | Forward | ATM IV | ATM strike | Quotes used |
|---|---|---|---|---|---|
| 2026-11-20 | 14 days | $249.80 | 36.76% | $250.45 | 9 |
| 2026-12-18 | 42 days | $250.30 | 51.34% | $254.13 | 16 |
| 2027-03-19 | 133 days | $252.54 | 44.06% | $261.63 | 12 |
| 2027-04-16 | 161 days | $253.68 | 43.28% | $264.38 | 11 |
| 2027-06-17 | 223 days | $255.08 | 42.22% | $269.35 | 14 |
| 2027-09-17 | 315 days | $257.93 | 40.72% | $277.06 | 19 |
Constant maturities
Interpolated between the bracketing listed expirations, in total variance
- 30 days
- 48.77%
- 60 days
- 48.28%
- 90 days
- 45.76%
- 180 days
- 42.88%
Interpolation is linear in total variance, not in volatility. Interpolating volatility directly implies a forward variance that can be negative between two expirations. A tenor beyond the longest listed expiration is reported as unavailable rather than extrapolated.
Term structure slope
Last 325 sessions
The dashed line marks 1.00, where the 90-day and 30-day at-the-money volatilities are equal. Above it the longer tenor carries the higher volatility.
The term structure is the at-the-money implied volatility of each listed expiration, plotted against how far away that expiration is. Its usual shape for a calm underlying slopes gently upward, because a longer horizon admits more uncertainty.
It inverts when the market prices a dated event: an expiration that captures a scheduled announcement carries the variance of that event on top of ordinary trading, so a shorter contract can print a higher volatility than a longer one.
Earnings
What the options priced in before each report, and what happened
Next report
How the pricing has held up
Over the last 7 reports
- Landed inside the implied band
- 6 of 7
- 86% — about 68% is what an exactly-priced event gives
- Mean implied move
- 6.2%
- Mean move that happened
- 11.7%
- absolute
Reports
Newest first. The implied move is one standard deviation, priced from the session before the release.
| Report | Session | Implied ± | Realised | Realised / implied |
|---|---|---|---|---|
| 2026-10-29 | Time not stated | 2.3% | +1.6% | 0.69× |
| 2026-10-28 | Before the open | 7.0% | -3.4% | 0.49× |
| 2026-07-29 | Before the open | — | — | — |
| 2026-07-01 | After the close | — | — | — |
| 2026-04-29 | Before the open | — | — | — |
| 2026-04-06 | Before the open | — | — | — |
| 2026-02-06 | Before the open | — | — | — |
| 2026-01-14 | After the close | — | — | — |
| 2025-10-30 | Before the open | — | — | — |
| 2025-10-14 | After the close | — | — | — |
| 2025-07-31 | Before the open | 8.0% | +1.1% | 0.13× |
| 2025-07-07 | After the close | 5.0% | +70.3% | 13.93× |
| 2025-05-01 | Before the open | 7.0% | -0.1% | 0.02× |
| 2025-02-12 | Before the open | 7.1% | -4.3% | 0.60× |
| 2024-10-30 | Before the open | 7.3% | -1.2% | 0.17× |
| 2024-08-01 | Before the open | — | — | — |
| 2024-04-24 | Before the open | — | — | — |
| 2024-02-13 | Before the open | — | — | — |
| 2023-11-08 | Before the open | — | — | — |
The implied move is read from the at-the-money straddle on the first expiration strictly after the report date, converted to a one-standard-deviation move and divided by the forward. Realised moves are the close-to-close return across the event, measured from the session before the release to the session after it.
Report dates that have already happened come from the company’s own 8-K filing and are exact. A date still in the future is either one the company has announced, or an estimate from its reporting cadence.