How to Hedge a Biotech Position Through a Binary Catalyst

The Problem

You are up 60% on a biotech stock ahead of its PDUFA date. If the FDA approves the drug, you might add 20%. If the agency issues a complete response letter (CRL), the formal rejection that tells a company what it must fix before the drug can be approved, you give back the entire gain in one morning. About 37% of new drug applications get a CRL, and pre-PDUFA stocks routinely drop 40-60% on the news. You are risking a 60-point loss to chase a 20-point gain. That is the wrong kind of asymmetric bet.

The Solution

Use options to put a floor under your downside through the event. Then be honest with yourself, because for most retail holders, trimming the position back to the 1-2% per-binary sizing rule is cheaper and simpler than engineering a hedge.

Step 1: Know Exactly What You Are Hedging

Start with the base rate. Across the 2018-2022 PDUFA cycles, roughly 37% of new drug applications received a CRL. When the letter lands, the moves are brutal and fast:

• Sesen Bio (SESN) dropped more than 80% in August 2021 after Vicineum, its bladder cancer drug, was rejected. It never recovered and was later delisted.
• Aldeyra (ALDX) dropped 75% in March 2026 on its third CRL for the dry-eye drug reproxalap.
• Capricor (CAPR) dropped 41% in September 2025 when deramiocel was rejected for Duchenne muscular dystrophy.

Approvals go the other way, but not by as much. The typical pre-PDUFA stock pops 30-50% on approval and drops 30-60% on a CRL. Your hedge is sized to the downside, not the upside.

Step 2: The Protective Put

A protective put is a put option you buy against shares you already own. It gives you the right to sell at a fixed strike, so no matter how far the stock falls, you can exit at your floor.

Strike selection is a tradeoff between cost and protection:

• An at-the-money put (strike at the current price) costs the most but floors you at roughly today’s level.
• A 5-10% out-of-the-money put is cheaper but lets you absorb the first 5-10% drop yourself.

The catch is implied volatility (IV) crush. The put is expensive precisely because everyone knows the catalyst date, and the options market has priced a 300% IV into the week before the PDUFA. When the decision lands, IV collapses whether the stock goes up or down. You pay up for the put anyway, because it is insurance against a known, dated risk, and insurance is never free when the house knows the storm is coming. If the stock actually drops 60%, the put’s intrinsic value dwarfs whatever premium you overpaid.

Step 3: The Collar

A collar finances the protective put by selling a covered call against the same shares. You buy a put below the market and sell a call above it. The call premium offsets the put cost, and in the right strikes the whole thing costs roughly zero.

Worked example on a $20 stock:

• Buy the $17.50 put for $0.75. This floors your loss at $2.50 per share, a 12.5% downside from here.
• Sell the $22.50 call for $0.75. This caps your gain at $2.50 per share, a 12.5% upside from here.
• Net cost: roughly $0.00.

If the drug is approved and the stock pops to $26, you are capped at $22.50 and you miss the last $3.50 per share. If the CRL hits and the stock falls to $8, you still sell at $17.50. You lose 12.5% instead of 60%. The collar is the cleanest way to lock in a gain without selling, and the tradeoff is always the same: you cap the approval upside.

Step 4: The Put Spread When IV Is Extreme

When pre-PDUFA IV is running at 300%, a naked put is genuinely expensive. A put spread buys a put and sells a lower-strike put, cutting your cost. But the floor now only holds down to the lower strike.

On the same $20 stock: buy the $17.50 put and sell the $12.50 put. Your net cost drops, but if the stock gaps below $12.50, you are fully exposed again below that level. A put spread is the right tool when you are willing to self-insure the tail below your sold strike. Most holders hedging a single binary event do not need to self-insure that deeply, so the simpler protective put or collar is usually the better fit.

Step 5: The Covered Call for a Post-Approval Holder

Once the drug is approved, a different pattern takes over: the sell-the-news fade. The stock pops on approval and then drifts down over the following weeks as traders who bought for the event take profits. If you intend to hold through that fade, writing a covered call is a legitimate way to generate income on the shares while you wait.

The one place you do not write a covered call is ahead of the binary event itself. Selling a call into a PDUFA date caps your upside right before the one moment the stock might double. If you want income before the decision, that is what the collar’s call leg is for, and it should be paired with a put, never sold naked.

Step 6: The Decision Table

Here is the honest read that most guides skip.

Situation	Best move
Position is already 1-2% of your portfolio	Do nothing. The sizing rule already did the hedging for you.
Position is 5%+ and you are up big	Trim back to 1-2%. Cheaper and simpler than any collar.
You must hold (taxes, conviction) and it is 5%+	Use a collar or protective put.
You hold through approval and expect a fade	Write a covered call after the pop, never before.

For most retail investors, trimming beats hedging. A collar has real friction: the options on small-cap biotechs are illiquid, and a wide bid-ask spread can eat 20-50% of your premium before the trade even starts. If your position is big enough to need a hedge, it was probably too big in the first place.

Common Mistakes

• Selling the collar’s call and then being surprised you missed the pop. You capped the upside on purpose. If you cannot stomach capping a 30% approval move, you did not actually want a collar.
• Buying a put on a stock you already sized correctly. A 1-2% position does not need a hedge. You are just paying IV crush for no reason.
• Hedging with options on an illiquid small cap. If the bid-ask spread is 30% wide, the hedge costs more than the downside it protects.
• Engineering a collar when the real problem is position size. The fix for a position that keeps you up at night is selling some of it, not buying options around it.

Final Checklist

• Know the CRL base rate: ~37%, and the typical drop: 40-60%
• Decide first whether trimming to 1-2% is simpler than any hedge
• If you hedge, pick the strike: at-the-money for max floor, 5-10% out for lower cost
• Use a collar to make the protection cost roughly zero
• Do not write a covered call ahead of the binary event itself
• Check option liquidity before you trade, a 30% spread is a dealbreaker

For the speculative side of the same trade, read how to trade biotech options through FDA catalysts. For the stock-side framework, start with the FDA catalyst trading guide, and for the 1-2% sizing rule, see how to build a biotech portfolio that survives CRLs. You can look up every recent CRL in the FDA’s searchable table at open.fda.gov.