SPRO Bear Put Spread Strategy
SPRO (Spero Therapeutics, Inc.), in the Healthcare sector, (Biotechnology industry), listed on NASDAQ.
Spero Therapeutics, Inc., a clinical-stage biopharmaceutical company, focuses on identifying, developing, and commercializing treatments for multi-drug resistant (MDR) bacterial infections and rare diseases in the United States. The company's product candidates include tebipenem pivoxil hydrobromide (HBr), an oral carbapenem-class antibiotic to treat complicated urinary tract infections, including pyelonephritis for adults; SPR206, a direct acting IV-administered agent to treat MDR Gram-negative bacterial infections in the hospital; and SPR720, an oral antibiotic for the treatment of non-tuberculous mycobacterial pulmonary disease. It has license agreement with Meiji Seika Pharma Co., Ltd. to support the development of tebipenem HBr; license agreement with Everest Medicines to develop, manufacture, and commercialize SPR206 in Greater China, South Korea, and Southeast Asian countries; collaboration agreement with Bill & Melinda Gates Medical Research Institute to develop SPR720 for the treatment of lung infections caused by Mycobacterium tuberculosis; and license agreement with Vertex Pharmaceuticals Incorporated for patents relating to SPR720, as well as SPR719, an active metabolite. The company was founded in 2013 and is headquartered in Cambridge, Massachusetts.
SPRO (Spero Therapeutics, Inc.) trades in the Healthcare sector, specifically Biotechnology, with a market capitalization of approximately $141.3M, a trailing P/E of 6.23, a beta of 1.43 versus the broader market, a 52-week range of 0.628-3.22, average daily share volume of 391K, a public-listing history dating back to 2017, approximately 32 full-time employees. These structural characteristics shape how SPRO stock options price implied volatility around earnings windows, capital events, and macro-driven sector rotations.
A beta of 1.43 indicates SPRO has historically moved more than the broader market, amplifying both the directional payoff and the realized volatility relative to an index-equivalent position. The trailing P/E of 6.23 is on the value side, where IV often compresses outside event windows because forward growth expectations are already discounted into the share price.
What is a bear put spread on SPRO?
A bear put spread buys an at-the-money put and sells an out-of-the-money put at a lower strike for defined risk and defined reward bounded by the strike width.
Current SPRO snapshot
As of May 15, 2026, spot at $2.79, ATM IV 64.50%, IV rank 9.48%, expected move 18.49%. The bear put spread on SPRO 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 bear put spread structure on SPRO specifically: SPRO IV at 64.50% is on the cheap side of its 1-year range, which favors premium-buying structures like a SPRO bear put spread, with a market-implied 1-standard-deviation move of approximately 18.49% (roughly $0.52 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 SPRO expiries trade a higher absolute premium for lower per-day decay. Position sizing on SPRO should anchor to the underlying notional of $2.79 per share and to the trader's directional view on SPRO stock.
SPRO bear put spread setup
The SPRO bear put spread below is built from the end-of-day chain, with each option leg priced at the bid/ask midpoint of its listed strike. With SPRO near $2.79, the first option leg uses a $2.79 strike; additional legs (when the strategy has them) anchor to spot-relative offsets. Premiums come from the bid/ask midpoint on the listed SPRO 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 SPRO shares for the stock leg in covered calls and collars).
| Action | Type | Strike / Basis | Premium (est) |
|---|---|---|---|
| Buy 1 | Put | $2.79 | N/A |
| Sell 1 | Put | $2.65 | N/A |
SPRO bear put spread risk and reward
- Net Premium / Debit
- N/A
- Max Profit (per contract)
- Unbounded
- Max Loss (per contract)
- Unbounded
- Breakeven(s)
- None on modeled curve
- Risk / Reward Ratio
- N/A
Max profit equals strike width minus net debit times 100; max loss equals net debit times 100. Breakeven is long-put strike minus net debit.
SPRO bear put spread payoff curve
Modeled P&L at expiration across a range of underlying prices for the bear put spread on SPRO. 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.
When traders use bear put spread on SPRO
Bear put spreads on SPRO reduce the cost of a bearish SPRO stock position by selling a lower-strike put; suited to moderate-decline theses where price reaches but does not vastly exceed the short strike.
SPRO thesis for this bear put spread
The market-implied 1-standard-deviation range for SPRO extends from approximately $2.27 on the downside to $3.31 on the upside. A SPRO bear put spread caps both the risk and the reward of a bearish position; relative to an outright long put on SPRO, the spread reduces the cost basis but limits the maximum profit to the strike width minus net debit. Current SPRO IV rank near 9.48% 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 SPRO at 64.50%. As a Healthcare name, SPRO options can move on sector-level news flow (peer earnings, regulatory updates, industry-specific macro data) in addition to SPRO-specific events.
SPRO bear put spread positions are structurally moderately bearish; 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. SPRO positions also carry Healthcare sector concentration risk; news flow inside the sector (peer earnings, regulatory shifts, supply-chain headlines) can move SPRO alongside the broader basket even when SPRO-specific fundamentals are unchanged. Long-premium structures like a bear put spread on SPRO are particularly exposed to IV-crush risk through scheduled events (earnings, FDA decisions, central-bank meetings) where IV typically contracts post-event regardless of the directional outcome. Always rebuild the position from current SPRO chain quotes before placing a trade.
Frequently asked questions
- What is a bear put spread on SPRO?
- A bear put spread on SPRO is the bear put spread strategy applied to SPRO (stock). The strategy is structurally moderately bearish: A bear put spread buys an at-the-money put and sells an out-of-the-money put at a lower strike for defined risk and defined reward bounded by the strike width. With SPRO stock trading near $2.79, the strikes shown on this page are snapped to the nearest listed SPRO chain strike and the premiums come straight from the end-of-day bid/ask midpoint.
- How are SPRO bear put spread max profit and max loss calculated?
- Max profit equals strike width minus net debit times 100; max loss equals net debit times 100. Breakeven is long-put strike minus net debit. For the SPRO bear put spread priced from the end-of-day chain at a 30-day expiry (ATM IV 64.50%), the computed maximum profit is unbounded per contract and the computed maximum loss is unbounded per contract. Live intraday quotes will differ as the chain moves through the trading session.
- What is the breakeven for a SPRO bear put spread?
- The breakeven for the SPRO bear put spread priced on this page is no defined breakeven on the modeled curve 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 SPRO market-implied 1-standard-deviation expected move is approximately 18.49%; if the move sits well outside the breakeven distance, the structure's risk-reward becomes correspondingly tighter.
- When should you consider a bear put spread on SPRO?
- Bear put spreads on SPRO reduce the cost of a bearish SPRO stock position by selling a lower-strike put; suited to moderate-decline theses where price reaches but does not vastly exceed the short strike.
- How does current SPRO implied volatility affect this bear put spread?
- SPRO ATM IV is at 64.50% with IV rank near 9.48%, 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.