Abivax Plummets 8.3%: Options Signal Deepening Bearish Sentiment as Biotech Sector Stumbles

Summary
• Abivax (ABVX) slumps 8.3% to $122.63, erasing $11M in turnover amid a $121.08–$133.10 intraday swing.
• Sector leader Amgen (AMGN) declines 2.5%, hinting at broader biotech sector fragility.
• Options chain surges in put volume, with ABVX20260109P119 and ABVX20260109P125 dominating liquidity.

Abivax’s sharp intraday selloff has ignited a frenzy in its options market, with bearish positioning intensifying as the stock trades near its 52-week low. The move coincides with a broader sector-wide correction, as Amgen’s 2.5% decline amplifies concerns over regulatory and macroeconomic headwinds. With technical indicators flashing mixed signals and options volatility spiking, traders are recalibrating strategies ahead of the January 9 expiration.

Biotech Sector Weakness Drives Abivax's Sharp Decline
The absence of company-specific news for Abivax contrasts sharply with the sector’s deteriorating sentiment. Amgen’s 2.5% intraday drop—its worst performance since late 2024—has triggered a flight to safety in biotech, with ABVX’s 8.3% plunge aligning with broader risk-off dynamics. The stock’s collapse into the $121–$122 support zone, coupled with a 1.55% turnover rate, suggests institutional selling pressure. While no regulatory or clinical setbacks have been announced, the sector’s sensitivity to interest rate expectations and R&D cost concerns is amplifying volatility.

Biotech Sector Under Pressure as Amgen Slides 2.5%
Abivax’s 8.3% drop mirrors the sector’s broader malaise, with Amgen’s 2.5% decline acting as a catalyst. While Amgen’s market cap dwarfs ABVX’s, both stocks are reacting to the same macroeconomic forces: rising borrowing costs for R&D-heavy firms and a cooling IPO market. The sector’s 52-week low for ABVX at $4.77 (vs. current $122.63) underscores the long-term volatility inherent in biotech, where clinical trial timelines and regulatory hurdles often overshadow short-term price swings.

Options Playbook: High-Leverage Puts Signal Aggressive Short-Side Potential
• MACD: 6.65 (above signal line 6.12), RSI: 50.49 (neutral), 200D MA: $57.53 (far below price), Bollinger Bands: $102.23–$150.74 (price near lower band)
• 30D MA: $124.49 (price below), 100D MA: $99.31 (price above), Turnover Rate: 1.55% (elevated)

Abivax’s technical profile reveals a stock caught between short-term bearish momentum and long-term bullish divergence. The 52-week low at $4.77 and 200D MA at $57.53 suggest structural support, but the 8.3% intraday drop has triggered a wave of put buying. Two contracts stand out for aggressive short-side positioning:

• ABVX20260109P119 (Put, $119 strike, 1/9 expiry):
- IV: 113.46% (high volatility)
- Leverage: 24.38% (moderate)
- Delta: -0.4005 (moderate sensitivity)
- Theta: -0.1746 (rapid time decay)
- Gamma: 0.0239 (modest sensitivity to price swings)
- Turnover: $38,078 (high liquidity)
- Payoff (5% downside): $2.50/share (strike $119 – projected $116.50)
This contract offers a 21% return on a 5% downside, with high IV and liquidity ensuring execution ease.

• ABVX20260109P125 (Put, $125 strike, 1/9 expiry):
- IV: 130.26% (extreme volatility)
- Leverage: 13.38% (high)
- Delta: -0.5338 (high sensitivity)
- Theta: -0.1172 (moderate time decay)
- Gamma: 0.0214 (modest sensitivity)
- Turnover: $90,107 (exceptional liquidity)
- Payoff (5% downside): $8.50/share (strike $125 – projected $116.50)
This high-leverage put thrives on a sharp selloff, with 70% return potential if the 52-week low test accelerates.

Hook: If $119 breaks, ABVX20260109P119 offers a 21% return on a 5% downside. Aggressive bears may consider ABVX20260109P125 for a 70% upside if the 52-week low test deepens.

Backtest Abivax Stock Performance
The backtest of ABVX's performance after an intraday plunge of -8% from 2022 to the present shows favorable short-to-medium-term gains. The 3-Day win rate is 50%, the 10-Day win rate is 52.19%, and the 30-Day win rate is 56.57%, indicating a higher probability of positive returns in the immediate aftermath of the plunge. The maximum return during the backtest was 19.44% over 30 days, suggesting that ABVX has the potential for recovery and even exceed pre-plunge levels.

Act Now: Biotech Volatility Prolongs, Puts Remain Strategic
Abivax’s 8.3% drop has crystallized a bearish inflection point, with sector-wide headwinds and technical indicators pointing to extended volatility. The 52-week low at $4.77 remains a critical psychological threshold, but the $119–$125 put options offer asymmetric rewards for a deepening selloff. With Amgen’s 2.5% decline signaling sector fragility, traders should prioritize liquidity-rich puts like ABVX20260109P119 and ABVX20260109P125. Watch for $119 breakdown or regulatory reaction—either could trigger a cascading move in biotech.