WST Butterfly Strategy
WST (West Pharmaceutical Services, Inc.), in the Healthcare sector, (Medical - Instruments & Supplies industry), listed on NYSE.
West Pharmaceutical Services, Inc. designs, manufactures, and sells containment and delivery systems for injectable drugs and healthcare products in the Americas, Europe, the Middle East, Africa, and the Asia Pacific. It operates in two segments, Proprietary Products and Contract-Manufactured Products. The Proprietary Products segment offers stoppers and seals for injectable packaging systems; syringe and cartridge components, including custom solutions for the needs of injectable drug applications, as well as administration systems that enhance the safe delivery of drugs through advanced reconstitution, mixing, and transfer technologies; and films, coatings, washing, and vision inspection and sterilization processes and services to enhance the quality of packaging components. It also provides drug containment solutions, including Crystal Zenith, a cyclic olefin polymer in the form of vials, syringes, and cartridges; and self-injection devices, as well as a range of integrated solutions, including analytical lab services, pre-approval primary packaging support and engineering development, regulatory expertise, and after-sales technical support. This segment serves biologic, generic, and pharmaceutical drug companies. The Contract-Manufactured Products segment is involved in the design, manufacture, and automated assembly of devices used in surgical, diagnostic, ophthalmic, injectable, and other drug delivery systems, as well as consumer products.
WST (West Pharmaceutical Services, Inc.) trades in the Healthcare sector, specifically Medical - Instruments & Supplies, with a market capitalization of approximately $21.36B, a trailing P/E of 40.12, a beta of 1.17 versus the broader market, a 52-week range of 202.79-330.88, average daily share volume of 911K, a public-listing history dating back to 1980, approximately 11K full-time employees. These structural characteristics shape how WST stock options price implied volatility around earnings windows, capital events, and macro-driven sector rotations.
A beta of 1.17 places WST roughly in line with broader market moves, so the strategy payoff and realized volatility track the index-equivalent baseline. The trailing P/E of 40.12 is on the rich side, which tends to correlate with higher earnings-window IV expansion as the market debates whether forward growth supports the multiple. WST pays a dividend, which adjusts put-call parity and shifts the ex-dividend pricing across the listed chain.
What is a butterfly on WST?
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 WST snapshot
As of May 15, 2026, spot at $304.98, ATM IV 34.50%, IV rank 17.22%, expected move 9.89%. The butterfly on WST 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 34-day expiry.
Why this butterfly structure on WST specifically: WST IV at 34.50% is on the cheap side of its 1-year range, which favors premium-buying structures like a WST butterfly, with a market-implied 1-standard-deviation move of approximately 9.89% (roughly $30.17 on the underlying). The 34-day window matched to the front-month expiry keeps theta exposure bounded while still capturing the post-snapshot move; longer-dated WST expiries trade a higher absolute premium for lower per-day decay. Position sizing on WST should anchor to the underlying notional of $304.98 per share and to the trader's directional view on WST stock.
WST butterfly setup
The WST 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 WST near $304.98, the first option leg uses a $290.00 strike; additional legs (when the strategy has them) anchor to spot-relative offsets. Premiums come from the bid/ask midpoint on the listed WST chain at a 34-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 WST shares for the stock leg in covered calls and collars).
| Action | Type | Strike / Basis | Premium (est) |
|---|---|---|---|
| Buy 1 | Call | $290.00 | $21.35 |
| Sell 2 | Call | $300.00 | $15.10 |
| Buy 1 | Call | $320.00 | $6.10 |
WST butterfly risk and reward
- Net Premium / Debit
- +$275.00
- Max Profit (per contract)
- $1,236.26
- Max Loss (per contract)
- -$725.00
- Breakeven(s)
- $312.75
- Risk / Reward Ratio
- 1.705
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.
WST butterfly payoff curve
Modeled P&L at expiration across a range of underlying prices for the butterfly on WST. 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% | +$275.00 |
| $67.44 | -77.9% | +$275.00 |
| $134.87 | -55.8% | +$275.00 |
| $202.30 | -33.7% | +$275.00 |
| $269.74 | -11.6% | +$275.00 |
| $337.17 | +10.6% | -$725.00 |
| $404.60 | +32.7% | -$725.00 |
| $472.03 | +54.8% | -$725.00 |
| $539.46 | +76.9% | -$725.00 |
| $606.89 | +99.0% | -$725.00 |
When traders use butterfly on WST
Butterflies on WST are pinning bets - traders use them when they expect WST 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.
WST thesis for this butterfly
The market-implied 1-standard-deviation range for WST extends from approximately $274.81 on the downside to $335.15 on the upside. A WST long call butterfly is a pinning play: it pays maximum at the middle strike if WST settles there at expiration, with the wing legs capping both the cost and the maximum loss to the net debit. Current WST IV rank near 17.22% 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 WST at 34.50%. As a Healthcare name, WST options can move on sector-level news flow (peer earnings, regulatory updates, industry-specific macro data) in addition to WST-specific events.
WST 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. WST positions also carry Healthcare sector concentration risk; news flow inside the sector (peer earnings, regulatory shifts, supply-chain headlines) can move WST alongside the broader basket even when WST-specific fundamentals are unchanged. Always rebuild the position from current WST chain quotes before placing a trade.
Frequently asked questions
- What is a butterfly on WST?
- A butterfly on WST is the butterfly strategy applied to WST (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 WST stock trading near $304.98, the strikes shown on this page are snapped to the nearest listed WST chain strike and the premiums come straight from the end-of-day bid/ask midpoint.
- How are WST 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 WST butterfly priced from the end-of-day chain at a 30-day expiry (ATM IV 34.50%), the computed maximum profit is $1,236.26 per contract and the computed maximum loss is -$725.00 per contract. Live intraday quotes will differ as the chain moves through the trading session.
- What is the breakeven for a WST butterfly?
- The breakeven for the WST butterfly priced on this page is roughly $312.75 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 WST market-implied 1-standard-deviation expected move is approximately 9.89%; if the move sits well outside the breakeven distance, the structure's risk-reward becomes correspondingly tighter.
- When should you consider a butterfly on WST?
- Butterflies on WST are pinning bets - traders use them when they expect WST 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 WST implied volatility affect this butterfly?
- WST ATM IV is at 34.50% with IV rank near 17.22%, 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.