BSX Options Chain Analysis

Delayed CBOE data, snapshot 2026-08-18. Spot $51.54.

Put/Call (OI)

0.38

269k P / 707k C

Put/Call (Volume)

1.29

15k P / 12k C today

30d ATM IV

36%

annualized implied move

Call wall

$85

113k contracts

Put wall

$40

100k contracts

Tail hedging

0.4×

deep-OTM puts vs calls

What the positioning says

●Bullish positioning: only 0.38 puts per call outstanding.
●Call wall at $85 (113k contracts), 65% above spot — the upside strike the crowd is already parked on; often acts as near-term resistance.
●Put wall at $40 (100k contracts), 22% below spot — the hedge floor; often acts as support.
●Deep-OTM call OI is 2.8× deep-OTM put OI — speculative upside positioning dominates the tails.

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 2026-09-18. 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 today
2026-08-21	89k	63k	0.70	8k
2026-08-28	2k	2k	0.66	2k
2026-09-04	1k	788	0.55	105
2026-09-11	2k	872	0.40	603
2026-09-18	155k	42k	0.27	5k
2026-09-25	667	2k	3.26	296
2026-10-02	675	99	0.15	608
2026-11-20	21k	19k	0.86	2k
2026-12-18	280k	68k	0.24	793
2027-01-15	79k	26k	0.32	5k
2027-02-19	2k	6k	3.21	593
2027-03-19	19k	11k	0.56	326
2027-06-17	18k	11k	0.62	2k
2028-01-21	37k	18k	0.50	1k

Source: CBOE delayed quotes, refreshed daily after US market close. Open interest is exchange-reported and lags one session. Research, not investment advice.