Why Merck and Pfizer Underperform Despite Solid Earnings Reports

U.S. equity futures painted an optimistic picture for Tuesday’s market open, with both the S&P 500 and Nasdaq positioned for modest gains. Yet in a striking divergence, two of the world’s largest pharmaceutical companies failed to capitalize on this positive sentiment. Merck and Pfizer’s shares underperform the broader market rally, with Merck retreating 1% and Pfizer dropping nearly 5%—a stark reminder that not all blue-chip companies move in sync with overall market momentum.

Pharma Stocks Underperform as Market Rallies

The underperformance of these pharmaceutical giants occurred despite the technology and gold sectors posting robust gains, creating a puzzling dynamic for investors. Both companies released results that, while respectable, failed to excite the market. This divergence highlights a critical juncture in the pharmaceutical industry, where earnings strength alone doesn’t guarantee stock appreciation. For Merck and Pfizer, various structural headwinds appear to be weighing on investor sentiment, even as their financial results demonstrate operational competence.

Merck’s Oncology Dominance and Revenue Stability

Merck demonstrated steady growth with global fourth-quarter sales reaching $16.4 billion, representing a 5% increase year-over-year, or 4% after adjusting for currency headwinds. Full-year revenue surpassed $65 billion, signaling a stable top-line performance. The company’s revenue engine remains anchored by oncology, where Keytruda continues to be the cornerstone. This cancer immunotherapy generated approximately $32 billion in annual sales—a remarkable 7% increase—and now represents nearly half of Merck’s total revenue.

This heavy reliance on Keytruda underscores both a strength and a vulnerability. While the drug’s sustained growth demonstrates Merck’s innovation capability in one of medicine’s most challenging domains, it also exposes the company to patent cliff risk. Merck faces the prospect of Keytruda exclusivity ending later this decade, a transition that markets appear to be factoring into their current underperformance.

New Products Provide Growth Runway for Merck

To hedge against future revenue pressures, Merck has strategically built out a portfolio of emerging therapies. The hypertension drug Winrevair achieved $1.4 billion in sales during its inaugural year—an impressive debut suggesting meaningful market adoption. The pneumococcal vaccine Capvaxix contributed just under $800 million, while the Animal Health division posted an 8% sales increase to $6.4 billion. These newer revenue streams collectively represent Merck’s strategic response to patent expiration risks.

For 2026, Merck projects approximately $66 billion in revenue, suggesting management’s confidence in maintaining current sales momentum. This guidance implies that new product contributions will offset anticipated declines elsewhere in the portfolio.

Pfizer’s Oncology Strength Amid Revenue Headwinds

Pfizer confronted greater challenges in 2025, with full-year revenue declining 2% to roughly $63 billion. However, the company’s oncology portfolio demonstrated particular resilience, with newer products like Padcev and Lorbrena helping counterbalance weakness in other therapeutic areas. On a adjusted basis, earnings per share increased 4% to $3.22, benefiting from improved operational margins and disciplined cost management.

Looking forward, Pfizer has provided 2026 guidance ranging from $59.5 billion to $62.5 billion in revenue, with adjusted EPS between $2.80 and $3.00. This guidance range reflects ongoing challenges from patent expirations and pricing pressures—factors that continue to constrain the company’s near-term growth trajectory.

Pipeline Strength and Future Outlook

Despite current headwinds, Pfizer’s management maintains an optimistic stance, citing a robust pipeline featuring approximately 20 pivotal studies slated to launch this year. This clinical-stage activity suggests potential catalysts for future growth, though markets remain cautious about timelines and ultimate commercial success.

Both Merck and Pfizer illustrate a broader pharmaceutical industry dynamic: large-cap companies can deliver financial results yet still underperform the broader market if their future growth prospects appear challenged. Patent expirations, pricing pressures, and competitive intensity all weigh on investor sentiment. Nevertheless, the resilience demonstrated by these two industry titans—their ability to maintain margins, develop new therapies, and navigate patent transitions—suggests that while their stocks may underperform in the near term, they remain strategically positioned for long-term sustainability in an evolving market landscape.