BIIB Options Chain Analysis

As of previous close (2026-10-16) · OPRA historical data

Spot $232.65 at that close. Nothing on this page comes from the session in progress.

Put/Call (OI)

0.73

20k P / 27k C

Put/Call (Volume)

0.49

715 P / 1k C that session

30d ATM IV

41%

annualized implied move

Call wall

$240

3k contracts

Put wall

$200

2k contracts

Tail hedging

3.9×

deep-OTM puts vs calls

What the positioning says

●Call wall at $240 (3k contracts), 3% above spot — the upside strike the crowd is already parked on; often acts as near-term resistance.
●Put wall at $200 (2k contracts), 14% below spot — the hedge floor; often acts as support.
●Deep-OTM put open interest is 3.9× deep-OTM call OI — an institutional hedging ladder sits under this stock.

Open interest by strike

All expiries combined. Amber lines mark the call and put walls; the dashed line is spot.

IV term structure

At-the-money implied volatility per expiry.

Volatility smile

IV by strike — expiry 2026-11-13. A steep left side = expensive downside protection.

30-day implied volatility history

Daily ATM IV (~30 DTE bucket) collected since March 2026. Rising IV into an event = the market bracing; collapsing IV after = the crush.

Open interest by expiry

Expiry	Call OI	Put OI	P/C	Volume that session
2026-10-23	1k	439	0.34	355
2026-10-30	503	481	0.96	55
2026-11-06	605	56	0.09	6
2026-11-13	25	37	1.48	95
2026-11-20	1k	189	0.16	567
2026-11-27	11	6	0.55	1
2026-12-18	6k	5k	0.96	101
2027-01-15	8k	7k	0.95	640
2027-03-19	2k	881	0.52	8
2027-04-16	136	184	1.35	5
2027-06-17	742	709	0.96	1
2027-09-17	315	38	0.12	0
2028-01-21	3k	1k	0.47	2
2029-01-19	55	6	0.11	1

Source: Cboe end-of-session option chains, summarized after each US market close and published from the following trading day — OPRA historical data. Under the OPRA plan options data becomes historical, and freely publishable, at the opening of the next trading session; data from the session in progress is never displayed or served here. Open interest is exchange-reported once a day. Research, not investment advice.