Mirum's Meteoric Surge: What's Fueling the 9.38% Intraday Rally?

Summary
• Mirum Pharmaceuticals (MIRM) surges 9.38% to $65.60, hitting its 52-week high of $66.40
• Q2 2025 revenue jumps 64% to $127.8M, exceeding expectations by $20.44M
• Analysts upgrade price targets to $89, with 10 firms maintaining 'Buy' ratings
• Institutional buying and bullish technicals amplify momentum

Mirum Pharmaceuticals has ignited a dramatic intraday rally, surging 10.23% to $66.105 as of 6:30 PM ET. The stock’s meteoric rise coincides with a flurry of analyst upgrades, robust Q2 earnings, and a bullish technical setup. With the biotech sector in flux and AMGN (Amgen) lagging, MIRM’s performance underscores its potential as a high-conviction play. This article dissects the catalysts, technicals, and options strategies for capitalizing on the momentum.

FDA Approval and Earnings Beat Ignite MIRM's Rally
Mirum’s 10.23% surge is driven by a perfect storm of analyst optimism, earnings outperformance, and pipeline catalysts. Stifel reinstated a 'Buy' rating with an $89 price target, while Evercore ISI and H.C. Wainwright raised their targets by 15.58% and 9.59%, respectively. Q2 2025 results showed a 64% revenue increase to $127.8M, with EPS of -$0.12 (vs. -$0.33 expected). The company’s cash-flow-positive commercial business, combined with pivotal PSC data in Q2 2026 and a blockbuster potential for volixibat, has energized investors. Institutional buying (e.g., Renaissance Technologies added 67.5% to its stake) and a 34.73% average analyst upside target further validate the move.

Biotech Sector Mixed as AMGN Dips, MIRM Soars
While MIRM’s rally defies the biotech sector’s mixed performance, Amgen (AMGN), the sector leader, fell 0.74% intraday. AMGN’s decline reflects broader market skepticism toward Big Pharma’s pricing pressures and R&D risks. In contrast, MIRM’s momentum is fueled by its niche focus on rare diseases and a pipeline with clear catalysts (e.g., PSC data in 2026). The stock’s 62.3% YoY revenue growth and 48% 2025 guidance raise outpace AMGN’s more diversified but slower-growth profile, highlighting MIRM’s asymmetric upside in a sector where specialization is rewarded.

Options and ETF Strategy for MIRM's Volatile Move
• MACD: 1.60 (bullish divergence), Signal Line: 0.94, Histogram: 0.66 (momentum)
• RSI: 81.62 (overbought), Bollinger Bands: $48.01–$57.86 (price at upper band)
• 200D MA: $45.85 (price above by 45%)

MIRM’s technicals suggest a continuation of the rally, with key support at $52.09 and resistance at $66.39 (52W high). The stock’s 34.73% average analyst upside and 64% revenue growth justify a bullish stance. For leveraged exposure, consider MIRM20250919C65 and MIRM20260116C65:

• MIRM20250919C65 (Call, $65 strike, 9/19 expiry):
- IV: 34.50% (moderate)
- Leverage: 18.21%
- Delta: 0.587 (moderate sensitivity)
- Theta: -0.074 (high time decay)
- Gamma: 0.0517 (high sensitivity to price swings)
- Turnover: $27,771 (liquid)
- Payoff (5% upside): $1.35 per contract (vs. $1.10 for a long stock position).
- Why it stands out: High gamma and moderate IV make it ideal for a short-term rally.

• MIRM20260116C65 (Call, $65 strike, 1/16/2026 expiry):
- IV: 35.74% (moderate)
- Leverage: 9.15%
- Delta: 0.601 (moderate sensitivity)
- Theta: -0.0276 (lower time decay)
- Gamma: 0.0248 (moderate sensitivity)
- Turnover: $48,146 (liquid)
- Payoff (5% upside): $1.35 per contract (vs. $1.10 for a long stock position).
- Why it stands out: Longer-dated option with lower theta decay, ideal for holding through Q4 catalysts.

Aggressive bulls should consider MIRM20250919C65 into a break above $66.39.

Backtest Mirum Stock Performance
Mirum Pharmaceuticals (MIRM) experienced a significant intraday surge of 10% on August 6, 2025, which was fueled by a coordinated analyst upgrade and revised revenue forecast. The stock's performance in the subsequent days was robust, with August 7, 2025, seeing a peak increase of 12.5% above the surge day's closing price. This indicates strong investor confidence, likely due to the positive earnings report and guidance raise.1. Sustainability of Gains: The stock's resilience and positive momentum suggest that the gains could be sustainable. Mirum's ability to maintain its 34.73% implied upside from current levels will be crucial in determining the sustainability of the surge.2. Support Levels: The stock showed support around the $35-$36 range, which could act as a floor if the stock were to experience a pullback. This support level is important to watch for any potential pullback in the stock price.3. Analyst Confidence: The surge was directly tied to a coordinated upgrade from 10 analysts, including Stifel’s reinstatement of a 'Buy' rating with an $89 price target. This analyst-driven momentum is a positive sign for the stock's future performance.In conclusion, Mirum's stock demonstrated strong resilience and positive momentum following the 10% intraday surge. The company's strong earnings report, increased revenue guidance, and positive analyst sentiment all contribute to a favorable outlook for the stock. However, the sustainability of the gains will depend on the company's continued performance and the ability to maintain its current upside potential.

Act Now: MIRM's Momentum and Analyst Optimism Signal Strong Near-Term Potential
Mirum’s 10.23% surge is underpinned by a rare alignment of analyst upgrades, earnings outperformance, and pipeline catalysts. The stock’s technicals (overbought RSI, bullish MACD) and 34.73% average analyst upside suggest the move is far from over. However, watch AMGN’s -0.74% decline as a sector barometer. For traders, the MIRM20250919C65 and MIRM20260116C65 options offer leveraged exposure to a stock with a 64% revenue growth trajectory. If $66.39 holds, the 52W high could be a springboard to $89. Position now—this is a high-conviction biotech breakout.