Market Plunge: Ionis Pharmaceuticals (NASDAQ: IONS) Leads Biotech Stock Decline Amid Clinical Trial Failure

• Ionis Pharmaceuticals (NASDAQ: IONS) Leads Major Stock Decliners After Phase 3 Trial Miss
• Clinical Trial Setback: Ionis Pharmaceuticals, Inc. (NASDAQ: IONS) experienced the largest decline after a Phase 3 study of eplontersen failed to meet its primary endpoint.
• Analyst Downgrades: Shares of Granite Construction Incorporated (NYSE: GVA) declined following a Goldman Sachs downgrade, while weakness in AeroVironment, Inc. (NASDAQ: AVAV) weighed on the leveraged Defiance Daily Target 2X Long AVAV ETF (NASDAQ: AVXX).
• Other Major Decliners: Cable One, Inc. (NYSE: CABO) and Polibeli Group Ltd (NASDAQ: PLBL) also recorded substantial losses, although no clear new company-specific catalyst was identified for either decline.

Several publicly traded companies recorded sharp share-price declines on July 9, 2026, despite gains across the broader U.S. stock market. The S&P 500 rose approximately 0.8%, while the Nasdaq Composite gained approximately 1.3%. The declines therefore appeared to reflect company-specific developments, analyst actions, and individual stock volatility rather than a broad market selloff.

The largest decline among the group was recorded by Ionis Pharmaceuticals, Inc. (NASDAQ: IONS), whose shares fell 23.90% to close at $64.27. The decline followed the announcement that the Phase 3 CARDIO-TTRansform study of eplontersen, marketed under the brand name Wainua, did not meet its primary endpoint.

Eplontersen is being developed with AstraZeneca PLC for patients with transthyretin-mediated amyloid cardiomyopathy, also known as ATTR-CM. The study did not demonstrate a statistically significant improvement in the primary composite endpoint of cardiovascular mortality and recurrent cardiovascular events. However, the companies reported a favorable safety profile and a nominally significant result in a prespecified subgroup of patients receiving eplontersen without a background transthyretin stabilizer.

Shares of Granite Construction Incorporated (NYSE: GVA) declined 12.50% to $125.58 after Goldman Sachs downgraded the stock from Neutral to Sell. The investment bank lowered its price target from $141 to $139, citing concerns that Granite’s operating improvements and favorable infrastructure trends were already reflected in its valuation.

Cable One, Inc. (NYSE: CABO) shares declined 13.70% to close at $35.27. No major company announcement or clearly identified same-day catalyst appeared to explain the decline. As a result, attributing the move to the company’s community initiatives or to broader market weakness would be speculative.

The Defiance Daily Target 2X Long AVAV ETF (NASDAQ: AVXX) declined 12.19% to $5.33. The leveraged ETF seeks to deliver approximately twice the daily percentage movement of AeroVironment, Inc. before fees and expenses.

Shares of AeroVironment, Inc. fell approximately 6% after RBC Capital Markets downgraded the stock from Outperform to Sector Perform and reduced its price target from $210 to $180. The decline in the underlying stock contributed directly to weakness in the leveraged ETF.

The AVXX decline was not caused by a newly announced reverse stock split. The fund previously completed a one-for-three reverse split in March 2026, several months before the July 9 trading session.

Meanwhile, shares of Polibeli Group Ltd (NASDAQ: PLBL) declined 14.06% to $6.42. No clear new company-specific announcement was identified as the primary cause of the decline. The stock had experienced substantial volatility following earlier news that the company was exploring a potential artificial intelligence computing center project in Thailand.

Overall, the day’s largest stock declines were driven by different factors rather than a broad market downturn. The Phase 3 trial miss directly affected Ionis Pharmaceuticals, Inc., while analyst downgrades pressured Granite Construction Incorporated and AeroVironment, Inc., contributing to the decline in the Defiance Daily Target 2X Long AVAV ETF. The sharp losses in Cable One, Inc. and Polibeli Group Ltd occurred without clearly identified same-day company announcements.