Adaptive Biotechnologies Plummets 15%: What's Behind the Sudden Selloff?

Summary
• Adaptive Biotechnologies (ADPT) trades at $14.79, down 15.29% intraday
• Insider selling of $17.86M in 90 days and Natera’s $275M Foresight acquisition fuel concerns
• Analysts raise price targets to $20–$21 despite 16.5% discount to 52-week high

Adaptive Biotechnologies faces a sharp intraday selloff amid mixed signals from institutional activity and insider exits. While Q3 revenue surged 102.4% to $93.97M, the stock failed to capitalize on analyst optimism. Short-term bearish momentum is amplified by a MACD crossover below the signal line and a 65.31 RSI near overbought territory, suggesting exhaustion in the rally.

Natera’s Acquisition Sparks Competitive Fears
The selloff in ADPT is driven by fears of Natera’s expansion into the MRD (Minimal Residual Disease) market. Natera’s $275M acquisition of Foresight Diagnostics, which owns the CLARITY MRD test, intensifies competition for Adaptive’s clonoSEQ diagnostic. Analysts warn this move accelerates Natera’s dominance in blood-cancer MRD testing, directly challenging Adaptive’s market position. Additionally, insider selling of 1.03M shares ($17.86M) and a post-earnings underreaction to Q3 revenue growth (102.4% YoY) exacerbate short-term bearish sentiment.

Biotech Sector Mixed as Thermo Fisher Holds Steady
The broader biotech sector shows divergence, with Thermo Fisher (TMO) down 0.17% despite ADPT’s collapse. TMO’s resilience highlights ADPT’s idiosyncratic weakness, driven by insider exits and technical breakdowns rather than sector-wide trends. While TMO’s stable performance suggests biotech fundamentals remain intact, ADPT’s sharp drop underscores its vulnerability to short-term sentiment shifts.

Bearish Plays and Volatility-Driven Options for ADPT
• 200-day MA: $11.60 (below), 50-day MA: $16.33 (broken)
• RSI: 65.31 (overbought), MACD: 0.74 (bearish crossover)
• Bollinger Bands: 11.80–21.42 (current price at 15.50, near lower band)

ADPT’s technicals signal a short-term bearish bias, with key support at $15.40 (intraday low) and resistance at $16.25 (intraday high). The 65.31 RSI suggests overbought conditions, while the MACD histogram’s negative divergence confirms weakening momentum. For options, focus on near-term puts with high leverage and implied volatility:

• ADPT20251219P15
- Strike: $15, Expiry: 12/19, IV: 74.04%, Delta: -0.348, Theta: -0.012, Gamma: 0.156, Turnover: 570

• ADPT20260116P17.5

Aggressive bears should prioritize ADPT20251219P15 for a near-term short, while ADPT20260116P17.5 suits those betting on extended volatility. Watch for a breakdown below $15.40 to trigger deeper technical damage.

Backtest Adaptive Stock Performance
I can back-test the “buy after a –15 % plunge” idea in two ways:1. Strict (uses intraday data): look for days where the stock’s intraday low is ≥ 15 % below the previous day’s close. • Requires minute-level data, which takes longer to pull and process.2. Practical proxy (fastest): treat any day whose close-to-close return ≤ –15 % as a “plunge” day. • Uses daily OHLC data, which is quick to retrieve and generally gives similar signals.Unless you specifically need minute-level precision, approach 2 is usually sufficient for this kind of historical test.Please let me know which approach you prefer so I can proceed with the data pull and event-based back-test.

Act Now: ADPT’s Short-Term Weakness May Offer Strategic Entry
ADPT’s 11.23% intraday drop reflects a mix of insider selling, earnings underreaction, and technical exhaustion. While the stock’s long-term fundamentals (102.4% revenue growth, $20.76 52-week high) remain intact, short-term bearish momentum is reinforced by a MACD crossover and RSI overbought warning. Traders should monitor the $15.40 support level and consider the ADPT20251219P15 put for a 5% downside scenario. Meanwhile, Illumina (ILMN), the sector leader, trades up 0.45%, signaling biotech resilience. Position now ahead of the 12/19 expiry to capitalize on near-term weakness.