Arcus Biosciences cae un 9.3%: ¿Qué está causando esta repentina caída en los precios de sus acciones?

Summary
• Morgan Stanley downgrades RCUS to Equalweight with $20 price target
• Insider sales trigger pre-market gap down to $22.14
• STAR-221 trial discontinuation removes key upside optionality
• Options chain shows heightened volatility with 10.4% short-term implied move

Arcus Biosciences (RCUS) is trading at a 9.3% intraday loss, plunging to $21.02 after a cascade of bearish catalysts. The stock’s sharp decline follows a Morgan Stanley downgrade, insider selling, and the discontinuation of a pivotal Phase 3 trial. With the 52-week low at $6.50 now within 70% of current levels, the sell-off has triggered a 10.4% implied volatility spike in options, signaling a critical inflection point for the biotech sector.

Downgrade, Insider Sales, and Trial Discontinuation Trigger Flight to Safety
Arcus Biosciences’ 9.3% intraday collapse stems from three compounding catalysts. First, Morgan Stanley’s downgrade from Overweight to Equalweight—coupled with a $20 price target—erased $3.20 of upside potential. Second, insider sales by President Juan C. Jaen and CFO Robert Goeltz II totaled $834,516, triggering a pre-market gap down to $22.14. Finally, the discontinuation of the STAR-221 trial for gastric cancer—a key value driver—removed incremental upside from domvanalimab and zimberelimab. These events collectively triggered a liquidity crunch, with the stock trading below its 50-day moving average of $22.55 and breaching critical support at $21.02.

Biotech Sector Mixed as Amgen Drags Down Peer Sentiment
The biotech sector remains fragmented, with Amgen (AMGN) down 3.26% on concerns over its oncology pipeline. While Arcus’ decline is stock-specific, the broader sector faces headwinds from regulatory scrutiny and profit-taking after a 32% Nasdaq Biotech Index gain in 2025. Arcus’ 172.9% six-month outperformance now appears unsustainable, with analysts shifting focus to Casdatifan’s incremental updates in 2026. However, the stock’s 10.4% short-term implied volatility outpaces sector averages, reflecting unique near-term risks.

Options and ETF Plays for a Volatile Biotech Rebound
• 52W High: $26.40 (7.7% above current price)
• 52W Low: $6.50 (71.6% below current price)
• RSI: 56.98 (neutral zone)
• MACD: 0.066 (bullish divergence)
• Bollinger Bands: $20.68 (lower band) to $25.32 (upper band)
• 200D MA: $13.21 (far below current price)

Arcus is trading near its 200-day moving average, with RSI in neutral territory and MACD showing a bullish divergence. The stock is oversold but lacks immediate catalysts for a rebound. For options traders, the RCUS20260116C20 call and RCUS20260116P25 put stand out. The call has a 11.11% leverage ratio and 0.65 delta, while the put offers 5.19% leverage and 0.70 delta. Both contracts have high implied volatility (102.76% and 81.40%) and moderate turnover (756 and 810).

RCUS20260116C20 (Call):
• Strike: $20 | Expiry: 2026-01-16 | IV: 102.76% | Delta: 0.65 | Theta: -0.123995 | Gamma: 0.109131 | Turnover: 756
• High leverage (11.11%) amplifies gains if the stock rebounds above $20
• Moderate delta (0.65) balances directional risk
• High gamma (0.109) ensures sensitivity to price swings
• Projected 5% downside scenario payoff: $0.525 (max(0, 21.0450.95 - 20))

RCUS20260116P25 (Put):
• Strike: $25 | Expiry: 2026-01-16 | IV: 81.40% | Delta: -0.70 | Theta: -0.034773 | Gamma: 0.064494 | Turnover: 810
• Strong put delta (-0.70) for bearish exposure
• High leverage (5.19%) for amplified downside capture
• Moderate gamma (0.064) for stability in volatile conditions
• Projected 5% downside scenario payoff: $3.975 (max(0, 25 - 21.0450.95))

Aggressive bulls may consider RCUS20260116C20 into a bounce above $20.50, while bears should target RCUS20260116P25 if the stock breaks below $21.00.

Backtest Arcus Biosciences Stock Performance
The backtest of RCUS's performance after a -9% intraday plunge from 2022 to now shows favorable short-to-medium-term gains. The 3-Day win rate is 49.80%, the 10-Day win rate is 51.78%, and the 30-Day win rate is 57.31%, indicating a higher probability of positive returns in the immediate aftermath of the plunge. The maximum return during the backtest period was 3.52%, which occurred on day 56, suggesting that while the ETF may experience fluctuations, it has the potential to recover and even exceed its pre-plunge levels.

Arcus at Crossroads: Watch for $20.50 Support or $25 Resistance
Arcus Biosciences’ 9.3% intraday plunge has created a critical juncture for the stock. With the 52-week low at $6.50 now within 70% of current levels, the immediate focus is on whether the $20.50 support (lower Bollinger Band) holds or if the stock accelerates toward $13.21 (200D MA). The options market is pricing in a 10.4% short-term move, suggesting high volatility ahead. Investors should monitor the STAR-121 trial results in Q1 2026 and Amgen’s -3.26% performance as sector sentiment barometer. For now, a break below $21.02 triggers a retest of $20.50, while a close above $22.50 (50D MA) could reignite buying interest. Watch for $20.50 breakdown or regulatory reaction.