How are BIIB butterfly max profit and max loss calculated?

Max profit equals the wing width minus net debit times 100 (reached when the underlying pins the middle strike); max loss equals the net debit times 100. Two breakevens at lower-wing plus debit and upper-wing minus debit. For the BIIB butterfly priced from the end-of-day chain at a 30-day expiry (ATM IV 31.56%), the computed maximum profit is $866.95 per contract and the computed maximum loss is -$125.00 per contract. Live intraday quotes will differ as the chain moves through the trading session.

What is the breakeven for a BIIB butterfly?

The breakeven for the BIIB butterfly priced on this page is roughly $186.25 and $203.75 at expiration, derived from end-of-day chain premiums. Breakeven is the underlying price at which the strategy's P&L crosses zero ignoring transaction costs and assignment risk. The current BIIB market-implied 1-standard-deviation expected move is approximately 9.05%; if the move sits well outside the breakeven distance, the structure's risk-reward becomes correspondingly tighter.

How does current BIIB implied volatility affect this butterfly?

BIIB ATM IV is at 31.56% with IV rank near 15.29%, which is on the low end of its 1-year range. Premium-buying structures (long call, long put, debit spreads) are relatively cheap in this regime; premium-selling structures collect less credit per unit risk.

BIIB Butterfly Strategy

BIIB (Biogen Inc.), in the Healthcare sector, (Drug Manufacturers - General industry), listed on NASDAQ.

Biogen Inc. discovers, develops, manufactures, and delivers therapies for treating neurological and neurodegenerative diseases. The company offers TECFIDERA, VUMERITY, AVONEX, PLEGRIDY, TYSABRI, and FAMPYRA for multiple sclerosis (MS); SPINRAZA for spinal muscular atrophy; and FUMADERM to treat plaque psoriasis. It also provides BENEPALI, an etanercept biosimilar referencing ENBREL; ADUHELM for the treatment of Alzheimer's disease; IMRALDI, an adalimumab biosimilar referencing HUMIRA; and FLIXABI, an infliximab biosimilar referencing REMICADE. In addition, the company offers RITUXAN for treating non-Hodgkin's lymphoma, chronic lymphocytic leukemia (CLL), rheumatoid arthritis, two forms of ANCA-associated vasculitis, and pemphigus vulgaris; RITUXAN HYCELA for non-Hodgkin's lymphoma and CLL; GAZYVA to treat CLL and follicular lymphoma; and OCREVUS for treating relapsing MS and primary progressive MS; and other anti-CD20 therapies. Further, it develops BIIB135, BIIB061, BIIB091, and BIIB107 for MS and neuroimmunology; Aducanumab, Lecanemab, BIIB076, and BIIB080 to treat Alzheimer's disease and dementia; BIIB067, BIIB078, BIIB105, BIIB100, and BIIB110 to treat neuromuscular disorders; BIIB124, BIIB094, BIIB118, BIIB101, and BIIB122 for treating Parkinson's disease and movement disorders; BIIB125 and BIIB104 for treating neuropsychiatry; Dapirolizumab pegol and BIIB059 to treat immunology related diseases; BIIB093 and BIIB131 to treat acute neurology; BIIB074 for neuropathic pain; and BYOOVIZ, BIIB800, and SB15 biosimilars, which are under various stages of development. The company has collaboration and license agreements with Acorda Therapeutics, Inc.; Alkermes Pharma Ireland Limited; Denali Therapeutics Inc.; Eisai Co., Ltd.; Genentech, Inc.; Neurimmune SubOne AG; Ionis Pharmaceuticals, Inc.; Samsung Bioepis Co., Ltd.; Sangamo Therapeutics, Inc.; and Sage Therapeutics, Inc.

BIIB (Biogen Inc.) trades in the Healthcare sector, specifically Drug Manufacturers - General, with a market capitalization of approximately $30.20B, a trailing P/E of 21.94, a beta of 0.20 versus the broader market, a 52-week range of 119.18-205.97, average daily share volume of 1.1M, a public-listing history dating back to 1991, approximately 8K full-time employees. These structural characteristics shape how BIIB stock options price implied volatility around earnings windows, capital events, and macro-driven sector rotations.

A beta of 0.20 indicates BIIB has historically moved less than the broader market, dampening realized volatility and producing tighter expected-move bands per unit of dollar exposure.

What is a butterfly on BIIB?

A long call butterfly buys one lower-strike call, sells two ATM calls, and buys one higher-strike call, paying a small net debit for a defined-risk position that maxes out if the underlying pins the middle strike at expiration.

Current BIIB snapshot

As of May 15, 2026, spot at $193.94, ATM IV 31.56%, IV rank 15.29%, expected move 9.05%. The butterfly on BIIB below is built from the same end-of-day chain, with strikes snapped to listed contracts and premiums pulled from the bid/ask midpoint at a 28-day expiry.

Why this butterfly structure on BIIB specifically: BIIB IV at 31.56% is on the cheap side of its 1-year range, which favors premium-buying structures like a BIIB butterfly, with a market-implied 1-standard-deviation move of approximately 9.05% (roughly $17.55 on the underlying). The 28-day window matched to the front-month expiry keeps theta exposure bounded while still capturing the post-snapshot move; longer-dated BIIB expiries trade a higher absolute premium for lower per-day decay. Position sizing on BIIB should anchor to the underlying notional of $193.94 per share and to the trader's directional view on BIIB stock.

BIIB butterfly setup

The BIIB butterfly below is built from the end-of-day chain, with each option leg priced at the bid/ask midpoint of its listed strike. With BIIB near $193.94, the first option leg uses a $185.00 strike; additional legs (when the strategy has them) anchor to spot-relative offsets. Premiums come from the bid/ask midpoint on the listed BIIB chain at a 28-day expiry; the cross-strike IV skew is reflected directly in the per-leg values rather than approximated. Quantity sizing assumes one contract per option leg (or 100 BIIB shares for the stock leg in covered calls and collars).

Action	Type	Strike / Basis	Premium (est)
Buy 1	Call	$185.00	$11.90
Sell 2	Call	$195.00	$6.45
Buy 1	Call	$205.00	$2.25

BIIB butterfly risk and reward

Net Premium / Debit: -$125.00
Max Profit (per contract): $866.95
Max Loss (per contract): -$125.00
Breakeven(s): $186.25, $203.75
Risk / Reward Ratio: 6.936

Max profit equals the wing width minus net debit times 100 (reached when the underlying pins the middle strike); max loss equals the net debit times 100. Two breakevens at lower-wing plus debit and upper-wing minus debit.

BIIB butterfly payoff curve

Modeled P&L at expiration across a range of underlying prices for the butterfly on BIIB. Each row is one sampled price point from the computed payoff curve; the full curve uses 200 price points internally before being summarized into 10 rows here.

Underlying Price	% From Spot	P&L at Expiration
$0.01	-100.0%	-$125.00
$42.89	-77.9%	-$125.00
$85.77	-55.8%	-$125.00
$128.65	-33.7%	-$125.00
$171.53	-11.6%	-$125.00
$214.41	+10.6%	-$125.00
$257.29	+32.7%	-$125.00
$300.17	+54.8%	-$125.00
$343.05	+76.9%	-$125.00
$385.93	+99.0%	-$125.00

When traders use butterfly on BIIB

Butterflies on BIIB are pinning bets - traders use them when they expect BIIB to settle near a specific level at expiration (often the prior close, a round number, or the max-pain strike) and want defined-risk exposure to that outcome.

BIIB thesis for this butterfly

The market-implied 1-standard-deviation range for BIIB extends from approximately $176.39 on the downside to $211.49 on the upside. A BIIB long call butterfly is a pinning play: it pays maximum at the middle strike if BIIB settles there at expiration, with the wing legs capping both the cost and the maximum loss to the net debit. Current BIIB IV rank near 15.29% sits in the lower third of its 1-year distribution, where IV often re-expands toward the mean; this favors premium-buying structures and disadvantages premium-selling structures on BIIB at 31.56%. As a Healthcare name, BIIB options can move on sector-level news flow (peer earnings, regulatory updates, industry-specific macro data) in addition to BIIB-specific events.

BIIB butterfly positions are structurally neutral / pin (limited-risk, limited-reward); the modeled P&L assumes European-style exercise at expiration and ignores early assignment, transaction costs, dividends paid before expiry on the stock leg (when present), and the bid-ask spread on the listed chain. BIIB positions also carry Healthcare sector concentration risk; news flow inside the sector (peer earnings, regulatory shifts, supply-chain headlines) can move BIIB alongside the broader basket even when BIIB-specific fundamentals are unchanged. Always rebuild the position from current BIIB chain quotes before placing a trade.

Frequently asked questions

What is a butterfly on BIIB?: A butterfly on BIIB is the butterfly strategy applied to BIIB (stock). The strategy is structurally neutral / pin (limited-risk, limited-reward): A long call butterfly buys one lower-strike call, sells two ATM calls, and buys one higher-strike call, paying a small net debit for a defined-risk position that maxes out if the underlying pins the middle strike at expiration. With BIIB stock trading near $193.94, the strikes shown on this page are snapped to the nearest listed BIIB chain strike and the premiums come straight from the end-of-day bid/ask midpoint.
How are BIIB butterfly max profit and max loss calculated?: Max profit equals the wing width minus net debit times 100 (reached when the underlying pins the middle strike); max loss equals the net debit times 100. Two breakevens at lower-wing plus debit and upper-wing minus debit. For the BIIB butterfly priced from the end-of-day chain at a 30-day expiry (ATM IV 31.56%), the computed maximum profit is $866.95 per contract and the computed maximum loss is -$125.00 per contract. Live intraday quotes will differ as the chain moves through the trading session.
What is the breakeven for a BIIB butterfly?: The breakeven for the BIIB butterfly priced on this page is roughly $186.25 and $203.75 at expiration, derived from end-of-day chain premiums. Breakeven is the underlying price at which the strategy's P&L crosses zero ignoring transaction costs and assignment risk. The current BIIB market-implied 1-standard-deviation expected move is approximately 9.05%; if the move sits well outside the breakeven distance, the structure's risk-reward becomes correspondingly tighter.
When should you consider a butterfly on BIIB?: Butterflies on BIIB are pinning bets - traders use them when they expect BIIB to settle near a specific level at expiration (often the prior close, a round number, or the max-pain strike) and want defined-risk exposure to that outcome.
How does current BIIB implied volatility affect this butterfly?: BIIB ATM IV is at 31.56% with IV rank near 15.29%, which is on the low end of its 1-year range. Premium-buying structures (long call, long put, debit spreads) are relatively cheap in this regime; premium-selling structures collect less credit per unit risk.