Prothena (PRTA) Options Chain
NASDAQ: PRTAHealth CareBiotechnology: Pharmaceutical PreparationsUSD
At close: Oct 9, 4:00 PM ET · Delayed 15 min
Expiration date
- Expiration
- Dec 18, 2026
- Days to expiration
- 68
- Share price
- $8.84
- Put/call ratio (OI)
- 1.00
- Put/call ratio (volume)
- 1.19
- Expected move
- ±$2.66
- Open interest (C / P)
- 2.47K / 2.46K
PRTA options summary
The PRTA options chain for the December 18, 2026 expiration lists 13 call and 7 put contracts, with 68 days until expiration. Open interest stands at 2,466 calls and 2,455 puts, a put/call ratio of 1.00, which is fairly balanced between calls and puts. At-the-money implied volatility near the $9.00 strike is 69.6%, which implies the market expects a move of about ±$2.66 (30.1%) in Prothena stock by expiration.
The most open interest sits at the $11.00 call (2.02K contracts) and the $6.00 put (2.00K contracts).
Summary generated from market data by MetaCap's automated system. Methodology
PRTA options chain · December 18, 2026
| Calls | Puts | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Last | Bid | Ask | Strike | Bid | Ask | Last | |||||
| 6.33 | 0.00 | 0.00 | 3.00 | — | — | — | |||||
| 4.50 | 0.00 | 0.00 | 5.00 | — | — | — | |||||
| 3.20 | 0.00 | 0.00 | 6.00 | 0.00 | 0.20 | 0.28 | |||||
| — | — | — | 7.00 | 0.50 | 0.80 | 0.65 | |||||
| 0.96 | 0.00 | 4.90 | 8.00 | 0.00 | 1.30 | 0.80 | |||||
| 0.45 | 0.00 | 1.80 | 9.00 | 0.00 | 2.50 | 1.10 | |||||
| 0.50 | 0.20 | 1.75 | 10.00 | 1.15 | 4.30 | 1.85 | |||||
| 0.25 | 0.00 | 0.80 | 11.00 | — | — | — | |||||
| 0.13 | 0.05 | 0.25 | 12.00 | — | — | — | |||||
| 0.55 | 0.00 | 1.50 | 13.00 | — | — | — | |||||
| 0.19 | 0.05 | 1.00 | 14.00 | — | — | — | |||||
| 0.15 | 0.00 | 0.00 | 15.00 | — | — | — | |||||
| 0.55 | 0.00 | 4.80 | 16.00 | — | — | — | |||||
| 0.55 | 0.00 | 4.80 | 18.00 | 7.00 | 11.90 | 9.61 | |||||
| — | — | — | 20.00 | 9.50 | 13.50 | 11.76 | |||||
In-the-money callsIn-the-money puts. IV = implied volatility, OI = open interest (contracts). Each contract covers 100 shares. Quotes delayed at least 15 minutes.
Frequently asked questions
What is the PRTA put/call ratio?
For the December 18, 2026 expiration, the PRTA put/call ratio based on open interest is 1.00 (2,455 puts vs 2,466 calls), and 1.19 based on today's volume. A ratio above 1 means more puts than calls.
What is PRTA's implied volatility?
At-the-money implied volatility for PRTA options expiring December 18, 2026 is about 69.6%, an annualized estimate of how much the market expects Prothena stock to move.
How many PRTA option expiration dates are there?
PRTA has 6 listed expiration dates, from Oct 16, 2026 to Jan 21, 2028.
What does "in the money" mean?
A call is in the money when the strike price is below the current share price; a put is in the money when the strike is above it. In-the-money contracts have intrinsic value and are shaded in the table.