Why Is Alnylam Pharmaceuticals (ALNY) Stock Down -23.94% Today?
Key Takeaways
- ALNY shares plunged approximately 23.94% in Thursday trading, falling from a prior close of $286.62 to around $218.01 intraday.
- The primary catalyst was a disappointing guidance revision. Alnylam cut its full-year 2026 TTR net product revenue guidance to $4.2–$4.5 billion, down from the previous range of $4.4–$4.7 billion.
- Q2 results were mixed: earnings per share of $1.84 beat the $1.60 consensus estimate, but revenue of $1.29 billion fell short of the $1.32 billion Wall Street expected.
- The revenue miss and guidance cut signal slowing momentum in the ATTR-CM launch of AMVUTTRA, Alnylam's flagship therapy, as pent-up demand normalizes.
- Broader biotech sentiment remains cautious, and the stock was already under pressure year-to-date, down roughly 27% heading into the report.
- Traders are now watching for competitor dynamics in the ATTR-CM space and upcoming pipeline catalysts including ALN-HTT02 data in Huntington's disease later this year.
Opening Summary
ALNY, the ticker for Alnylam Pharmaceuticals, Inc. — the Cambridge, Massachusetts-based pioneer of RNA interference (RNAi) therapeutics — suffered one of its steepest single-day selloffs in recent memory on Thursday. As of midday trading, shares were down roughly 23.94%, plunging from Wednesday's closing price of $286.62 to approximately $218.01. The collapse followed the company's second-quarter 2026 earnings release, which revealed a top-line revenue miss and, more critically, a sharp downward revision to full-year revenue guidance, shaking investor confidence in the growth trajectory of Alnylam's flagship TTR franchise.
Q2 Earnings: A Mixed Report Overshadowed by Guidance
Alnylam reported second-quarter 2026 total revenues of $1.29 billion, representing 67% year-over-year growth but falling short of the $1.32 billion consensus estimate. On the bottom line, the company delivered earnings per share of $1.84, exceeding the $1.60 analysts had projected. Net product revenues reached $1.17 billion, anchored by the TTR franchise — comprising AMVUTTRA (vutrisiran) and ONPATTRO (patisiran) — which generated $1.03 billion, an 89% increase compared to Q2 2025.
Despite the solid headline growth figures, the market seized on a much larger concern: management's revised full-year outlook. Alnylam lowered its 2026 TTR net product revenue guidance to a range of $4.2 billion to $4.5 billion, down from the prior $4.4 billion to $4.7 billion. The new total revenue forecast of $4.20 billion to $4.50 billion landed well below the analyst consensus of approximately $5.61 billion, triggering an immediate and severe repricing of the stock.
AMVUTTRA and the Normalization of ATTR-CM Demand
At the center of the guidance cut is AMVUTTRA, Alnylam's cornerstone therapy for transthyretin-mediated (ATTR) amyloidosis with cardiomyopathy (ATTR-CM). CEO Yvonne Greenstreet addressed the revision directly, explaining that the company is seeing "the normalization of growth in second line volume after satisfying pent-up demand from patients waiting for a new therapy." In simpler terms, the initial surge of patients who had been awaiting a novel ATTR-CM treatment option has now largely been absorbed, and the pace of new patient starts is decelerating toward a more sustainable — but lower — run rate.
This normalization dynamic is not uncommon in high-profile drug launches, but Alnylam's premium valuation — the stock traded at a forward P/E multiple above 30 before the selloff — left no room for growth disappointment. The guidance cut reframed the narrative from one of explosive, unconstrained growth to a more measured ramp that will require deeper market penetration, earlier diagnosis initiatives, and competitive positioning against rivals such as PFE (Pfizer's Vyndaqel/Vyndamax) and BBIO (BridgeBio's Attruby).
Market Context and Trading Activity
The magnitude of Thursday's selloff was amplified by the stock's already fragile technical position. ALNY entered the session down roughly 27% year-to-date and had lost more than 40% from its 52-week high of $495.55 reached in October 2025. Trading volume surged dramatically, with the stock on pace to record several times its average daily turnover, reflecting broad-based institutional repositioning. The selloff was not driven by a single downgrade or sector-wide rout — the broader biotech sector and major indices were relatively stable — but rather by a stock-specific fundamental reassessment that had been building for months.
The move also broke through several key technical levels. Prior support near the $260–$265 zone, which had held during the July selloff, was decisively breached, leaving the stock trading at levels not seen since early 2023 on an adjusted basis.
What Comes Next for ALNY
Looking ahead, investors will focus on several factors that could stabilize or further pressure the stock. Management emphasized that it remains confident in the long-term trajectory of the ATTR-CM launch and continues to invest robustly in the franchise, including AI-enabled screening collaborations and real-world evidence studies such as DemonsTTRate. The company also highlighted pipeline progress, with Phase 2 initiations for ALN-6400 in von Willebrand disease and mivelsiran in Down syndrome-associated Alzheimer's disease, as well as the upcoming presentation of Phase 1 data for ALN-HTT02 in Huntington's disease at the EHDN Congress in October.
Key risks include further competitive encroachment in ATTR-CM, potential pricing pressure, and execution risk across the broad pipeline. On the regulatory front, a decision on cemdisiran from Regeneron for generalized myasthenia gravis — for which Alnylam would earn royalties — is expected by November 2026. With cash and marketable securities of $3.3 billion, the company has ample runway, but restoring investor confidence will require demonstrable execution against the revised guidance and tangible pipeline catalysts in the months ahead.
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ALNY in downward trend: 10-day moving average broke below 50-day moving average on July 20, 2026
The 10-day moving average for ALNY crossed bearishly below the 50-day moving average on July 20, 2026. This indicates that the trend has shifted lower and could be considered a sell signal. In of 19 past instances when the 10-day crossed below the 50-day, the stock continued to move higher over the following month. The odds of a continued downward trend are .
Technical Analysis (Indicators)
Bearish Trend Analysis
The Stochastic Oscillator demonstrated that the ticker has stayed in the overbought zone for 5 days. The longer the ticker stays in the overbought zone, the sooner a price pull-back is expected.
Following a 3-day decline, the stock is projected to fall further. Considering past instances where ALNY declined for three days, the price rose further in of 62 cases within the following month. The odds of a continued downward trend are .
ALNY broke above its upper Bollinger Band on August 19, 2026. This could be a sign that the stock is set to drop as the stock moves back below the upper band and toward the middle band. You may want to consider selling the stock or exploring put options.
The Aroon Indicator for ALNY entered a downward trend on August 10, 2026. This could indicate a strong downward move is ahead for the stock. Traders may want to consider selling the stock or buying put options.
Bullish Trend Analysis
The RSI Indicator points to a transition from a downward trend to an upward trend -- in cases where ALNY's RSI Indicator exited the oversold zone, of 24 resulted in an increase in price. Tickeron's analysis proposes that the odds of a continued upward trend are .
The Momentum Indicator moved above the 0 level on August 13, 2026. You may want to consider a long position or call options on ALNY as a result. In of 82 past instances where the momentum indicator moved above 0, the stock continued to climb. The odds of a continued upward trend are .
The Moving Average Convergence Divergence (MACD) for ALNY just turned positive on August 14, 2026. Looking at past instances where ALNY's MACD turned positive, the stock continued to rise in of 48 cases over the following month. The odds of a continued upward trend are .
Following a 3-day Advance, the price is estimated to grow further. Considering data from situations where ALNY advanced for three days, in of 301 cases, the price rose further within the following month. The odds of a continued upward trend are .
Fundamental Analysis (Ratings)
The Tickeron SMR rating for this company is (best 1 - 100 worst), indicating very strong sales and a profitable business model. SMR (Sales, Margin, Return on Equity) rating is based on comparative analysis of weighted Sales, Income Margin and Return on Equity values compared against S&P 500 index constituents. The weighted SMR value is a proprietary formula developed by Tickeron and represents an overall profitability measure for a stock.
The Tickeron Price Growth Rating for this company is (best 1 - 100 worst), indicating slightly worse than average price growth. ALNY’s price grows at a lower rate over the last 12 months as compared to S&P 500 index constituents.
The Tickeron Valuation Rating of (best 1 - 100 worst) indicates that the company is significantly overvalued in the industry. This rating compares market capitalization estimated by our proprietary formula with the current market capitalization. This rating is based on the following metrics, as compared to industry averages: P/B Ratio (23.364) is normal, around the industry mean (20.145). P/E Ratio (41.153) is within average values for comparable stocks, (22.992). Projected Growth (PEG Ratio) (0.449) is also within normal values, averaging (3.861). Dividend Yield (0.000) settles around the average of (0.018) among similar stocks. P/S Ratio (6.821) is also within normal values, averaging (444.692).
The Tickeron Profit vs. Risk Rating rating for this company is (best 1 - 100 worst), indicating that the returns do not compensate for the risks. ALNY’s unstable profits reported over time resulted in significant Drawdowns within these last five years. A stable profit reduces stock drawdown and volatility. The average Profit vs. Risk Rating rating for the industry is 92, placing this stock better than average.
The Tickeron PE Growth Rating for this company is (best 1 - 100 worst), pointing to worse than average earnings growth. The PE Growth rating is based on a comparative analysis of stock PE ratio increase over the last 12 months compared against S&P 500 index constituents.
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General Information
a developer of therapeutics based on RNA interference
Industry Biotechnology
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