Prothena (PRTA) Options Chain
NASDAQ: PRTAHealth CareBiotechnology: Pharmaceutical PreparationsUSD
At close: Oct 9, 4:00 PM ET · Delayed 15 min
Expiration date
- Expiration
- Nov 20, 2026
- Days to expiration
- 40
- Share price
- $8.84
- Put/call ratio (OI)
- 0.01
- Put/call ratio (volume)
- 0.00
- Expected move
- ±$2.61
- Open interest (C / P)
- 158 / 1
PRTA options summary
The PRTA options chain for the November 20, 2026 expiration lists 4 call and 1 put contracts, with 40 days until expiration. Open interest stands at 158 calls and 1 puts, a put/call ratio of 0.01, which is tilted bullish, with calls outnumbering puts. At-the-money implied volatility near the $9.00 strike is 89.4%, which implies the market expects a move of about ±$2.61 (29.6%) in Prothena stock by expiration.
The most open interest sits at the $8.00 call (80 contracts) and the $9.00 put (1 contracts).
Summary generated from market data by MetaCap's automated system. Methodology
PRTA options chain · November 20, 2026
| Calls | Puts | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Last | Bid | Ask | Strike | Bid | Ask | Last | |||||
| 1.96 | 0.75 | 3.20 | 7.00 | — | — | — | |||||
| 0.84 | 0.00 | 2.45 | 8.00 | — | — | — | |||||
| 0.81 | 0.00 | 1.25 | 9.00 | 0.00 | 3.00 | 0.82 | |||||
| 0.25 | 0.25 | 0.45 | 10.00 | — | — | — | |||||
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 November 20, 2026 expiration, the PRTA put/call ratio based on open interest is 0.01 (1 puts vs 158 calls), and 0.00 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 November 20, 2026 is about 89.4%, 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.